KR20070008028A - Method for controlling operation mode in a subscriber station of wireless communication system and the subscriber station - Google Patents

Abstract

A method for controlling an operation of a terminal in a wireless communication system and the terminal are provided to lengthen the life span of a battery of a terminal by inducing the terminal to be operated in a low power mode by enabling the terminal, being in idle mode, to release connection through a DREG-REQ(CMD) message exchanging procedure. A base station change determining unit(14) determines whether a terminal has moved to a different base station region based on a DL(Downlink)-MAP received from a listening window of a sleep mode. When the terminal is determined to have moved to a different base station region, an operation mode controller(16) releases the sleep mode, performs transition to a normal mode, and resets a period Tidle for entering an idle mode.

Description

METHOD FOR CONTROLLING OPERATION MODE IN A SUBSCRIBER STATION OF WIRELESS COMMUNICATION SYSTEM AND THE SUBSCRIBER STATION}

1 is a block diagram illustrating a general broadband wireless communication system;

2 illustrates a case in which a terminal moves a service area in a wireless communication system;

3 is a diagram illustrating an example in which a terminal operates a sleep mode and an idle mode according to an embodiment of the present invention;

4 is a block diagram of a terminal according to an embodiment of the present invention;

5 is a flowchart illustrating an operation mode control in a terminal according to an embodiment of the present invention.

The present invention relates to a method of controlling an operation mode in a terminal of a wireless communication system and a terminal thereof.

1 is a diagram illustrating a configuration of a general wireless communication system. Referring to FIG. 1, each MSS 10, 12 is generally mobile and is connected to the backbone network 30 via a base station (BS) 20, 22, respectively. The MSS 10, 12 allows access between the BS 20, 22 and the subscriber. Base stations (20, 22) provide control, management, and connectivity to the MSS (10, 12). In addition, the backbone network 30 is connected to an Authentication and Service Authorization Server (ASA) 40 for authentication and service authentication of the MSS 10 and 12.

On the other hand, reducing power consumption is very important for MSS supporting mobility. One method for reducing power consumption of the MSS is to adopt a sleep mode or an idle mode. The sleep mode or idle mode is a power saving mode.

In the sleep mode or idle mode, the MSS stops all functions other than the real time clock (RTC) and phase locked loop (PLL), for example, the transmit function, the receive function, and the like. At this point, the PLL is active so that it can be restarted. In addition, the MSS periodically wakes up in the sleep mode or idle mode to perform searching and ranging or handover for neighbor BSs. Wireless communication systems, such as the IEEE 802.16e system, utilize this sleep or idle mode to reduce the power consumption of the MSS.

First, the sleep mode operation is started by the terminal transmits a MOB-SLP-REQ message. The MOB-SLP-REQ message includes initial sleep-window (= 8 bits) that specifies the first sleep-window for each Power Saving class, and final sleep-window base (= 10 bits) that specifies the last sleep-window, and final- It consists of a sleep-window exponent (= 3 bits) and a listening-window (= 4 bits) that sets the listening-window. The sleep state operation requested by the UE through the MOB-SLP-REQ message is finally acknowledged through the MOB-SLP-RSP message of the base station, and when the UE sets TRF-IND required to 1 through the MOB-SLP-RSP message. It receives its own SLPID and operates sleep mode through the same process. sleep and listening-window are frame-based, and the sleep-window update algorithm is as follows. Based on the initial sleep-window, the subsequent sleep-window is doubled in length, and the final sleep-window is final-sleep-window = final-sleep-window base × 2 ^{(final-sleep-window exponent)} It is set, and does not double after the final sleep-window, and continues to hold the final sleep-window value.

The Idle mode operation starts when the terminal transmits a DREG-REQ message and receives a DREG-CMD message from the base station. In the DREG-REQ message, a paging cycle (= 16 bits) requested by the terminal is defined, and the DREG-REQ is defined. Paging Group ID (= 8 bits), Paging Offset (= 8 bits) and Paging Cycle (= 16 bits) are defined in the DREG-CMD transmitted by the base station receiving the message. Upon receiving this, the mobile station considers the Paging Interval for 5 frames from the frame whose frame number (= FN) satisfying the FN% Paging Cycle = Paging Offset and is transmitted from the base station during this period. Receive a PAG-ADV message. The MOB-PAG-ADV message should be performed for each terminal and MAC address hash information indicating the Paging Group ID to which the base station transmitting the message belongs and terminals requiring Location Update or Network Re-entry among the terminals operating in Idle mode. It consists of Action code describing the procedure. If the paging group ID is different between the base station receiving the DREG-CMD message and the base station transmitting the current MOB-PAG-ADV message before entering the idle mode, perform a location update or for each terminal in the idle mode. A series of procedures are performed according to the action code defined by the base station.

In the conventional standard, only the independent division between the sleep mode and the idle mode is made, and there is no state in which a specific state is to be entered in the sleep mode or the idle mode. In the implementation process, only the sleep mode or the idle mode can be operated independently, but in order for two modes to exist simultaneously and operate flexibly with each other, an efficient transition method from the normal mode to the sleep mode or the idle mode is required.

Accordingly, the present invention provides a mode transition method for flexibly operating the sleep mode and the idle mode operating without correlation with each other in the conventional standard and a wireless communication system for the same.

To this end, in a terminal communicating with a base station in a wireless communication system according to an embodiment of the present invention, the base station change determination unit for determining whether the mobile station has moved to another base station area based on the DL-MAP received in the listening window in the sleep mode. And an operation mode control unit for canceling the sleep mode, transitioning to the normal mode, and resetting the period Tidle for entering the idle mode when determining that the mobile station has moved to another base station area.

In addition, an embodiment of the present invention is a method for controlling an operation mode in a terminal communicating with a base station of a wireless communication system, which determines whether a mobile station has moved to another base station based on a DL-MAP received in a listening window of a sleep mode. And a process of canceling the sleep mode and transitioning to the normal mode if it is determined to move to another base station area, and resetting the period Tidle for entering the idle mode.

 Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

First, with reference to Figures 2 and 3, the operation of the sleep mode and the idle mode when the terminal moves the service area in the wireless communication system according to an embodiment of the present invention.

2 is a diagram illustrating a case in which a terminal moves a service area in a wireless communication system, and FIG. 3 is a diagram illustrating an example in which a terminal operates a sleep mode and an idle mode according to an embodiment of the present invention.

Referring to FIG. 2, in order to enter a sleep mode or an idle mode, the terminal 10 enters each mode when there is no traffic in DL / UL during a Tsleep and Tidle period, respectively. In the embodiment of the present invention, the operation of the terminal will be described under the assumption that Tidle> Tsleep. Since the Tsleep period is shorter than the Tidle period, the UE 10 enters the sleep mode after exchanging the Tsleep 102 at the base station 20 that has performed the current network entry 102 after the MOB-SLP-REQ (RSP) message (104). .

Then, when the terminal 10 moves, for example, from the service area 50 by the base station 20 to the service area 52 by the base station 22, a handover occurs. A base station that has provided a service to the terminal 10 is called a serving base station, and a base station that will provide a service to the terminal 10 later is called a target base station. However, when the terminal 10 is in the sleep window period of the sleep mode, for example, the sleep window 86 of FIG. 3, since the terminal 10 stops communication with the base stations 20 and 22, the terminal 10 stops communicating with the serving base station 20. It is not known that the service area 50 has moved from the service area 50 to the service area 52 by the target base station 22.

When the terminal 10 receives the first frame from the base station 22 in the listening window that appears after the sleep window, the terminal 10 checks the base station information. For example, the terminal 10 may receive a frame number (FN) and base station ID (BS-ID) information defined in the DL-MAP of the first frame received in the listening window 87 subsequent to the sleep window 86 of FIG. 3. Any one or combination thereof is compared with any one or combination thereof of the expected frame number (FN) and base station ID (BS-ID) information calculated based on the previous listening window.

For example, in FIG. 3, the terminal 10 listens to one or a combination of an expected FN and a base station ID (BS-ID #N) according to the FN defined in the DL-MAP received in the previous listening window 84 and the current listening. When one or a combination of the frame number (FN) and the base station ID (# N + 1) information defined in the DL MAP received in the window 87 is compared and different, the mobile station moves to another base station area during the sleep window. Then the sleep mode is canceled and then the normal mode is changed. The terminal 10 may reset the Tidle period as follows. Here, Tlastsleepwnd is the last sleep window section just before the transition to Normal mode, and Tlistenwnd is the listening window value that appears after Tlastsleepwnd.

1) Tlastsleepwnd <= Existing Tidle

   Tidle = Tidle-Tlastsleepwnd

2) Tlastsleepwnd> Existing Tidle

   Tidle = Tlistenwnd

First, a case in which Tlastsleepwnd <= existing Tidle will be described. Since the terminal 10 has no traffic transmitted to itself or no traffic to transmit itself in the last sleep window 86, no traffic should be generated to enter the idle mode. In the Tidle, which is the interval, the Tlastsleepwnd, in which previous traffic did not occur, is subtracted. That is, the terminal 10 reflects Tlastsleepwnd in which no previous traffic has occurred and does not count a Tidle according to the handover to the Tidle.

In addition, in the case of Tlastsleepwnd> existing Tidle, the terminal 10 has transitioned to the normal mode in the state of not determining the DL traffic through the MOB-TRF-IND message received from the listening window 87 according to the handover. Therefore, the Tidle period can be set to the listening window (87) that appears after Tlastsleepwnd, that is, Tlistenwnd.

Meanwhile, the terminal 10 moving to another base station 22 performs the initial cell search again in the normal mode. After performing cell discovery and network entry procedures (106), if DL / UL traffic does not occur during the Tsleep, Reset Tidle period (110), a procedure that matches the timer, that is, sleep mode or idle mode, that is, power saving Perform a message exchange procedure to enter power saving mode.

If the Tsleep is smaller than the Tidle, the Tsleep period expires first and the terminal 10 enters the sleep mode through the MOB-SLP-REQ (RSP) message exchange procedure with the base station 22, which is synchronized through the cell discovery procedure. Do this.

Otherwise, when the Tidle is smaller than the Tsleep, the Tidle period expires first, and thus the terminal 10 enters the idle mode through the DREG-REQ (CMD) message exchange procedure with the base station 22 synchronized with the cell discovery procedure. Perform. However, if DL / UL traffic occurs after completing a network entry situation with a newly synchronized base station, the timer operation corresponding to the Tsleep and Tidle periods operated after the network entry is stopped and restarted. Update to the initially set Tidle value.

4 is a block diagram of a terminal according to an embodiment of the present invention. Referring to FIG. 4, the terminal 10 according to an embodiment of the present invention includes a transceiver 12, a base station change plate end 14, and an operation mode controller 16. The terminal 10 transmits and receives data with the base station through the transceiver 12. The transceiver 12 provides the downlink control message received from the base station in the listening window in the sleep mode to the base station change determination unit 14. The base station change determination unit 14 estimates any one or a combination of FNs and base station ID information defined in the DL-MAP of the current downlink control message from the FN immediately before the sleep mode transition and the known base station ID information. Comparison with any one or a combination thereof. Alternatively, when the base station change determination unit 14 is already operating in the sleep mode, the expected FN based on the DL-MAP received from the previous listening window or any combination of FN and base station ID information defined in the current DL-MAP and a combination thereof. And base station ID information.

The base station change determination unit 14 identifies a new base station if any one or a combination of the FN and the base station ID information of the current DL-MAP is different from any one or a combination of the expected FN and the known base station ID information. In other words, the base station change determination unit 14 determines that the service base station of the terminal 10 has been changed by handoff or the like and informs the operation mode control unit 16 of this. The operation mode controller 16 transitions to the normal mode after canceling the sleep mode. Subsequently, the operation mode controller 16 may reset the Tidle period. When Tlastsleepwnd, which is the last sleep window time just before the transition in Normal mode, is <= existing Tidle, the operation mode controller 16 does not count the Tidle anew and reflects Tlastsleepwnd to which the previous traffic did not occur. Subtract Tlastsleepwnd you did not. The operation mode control unit 16 sets the Tidle period to Tlistenwnd when Tlastsleepwnd is> existing Tidle. The reason for this is to determine the presence or absence of DL traffic through the MOB-TRF-IND message received from the listening window 87 according to the handover. This is because you have transitioned to normal mode without doing so.

On the other hand, if the DL / UL traffic does not occur during the Tsleep, the reset Tidle period, the operation mode control unit 16 performs a procedure suitable for the timer, that is, a message exchange procedure for entering the sleep mode or the idle mode. If the Tsleep is smaller than the Tidle, the Tsleep period expires first and the operation mode controller 16 sleeps through the MOB-SLP-REQ (RSP) message exchange procedure with the base station 22, which is synchronized through the cell search procedure. Perform the entry into. Otherwise, if the Tidle is smaller than Tsleep, when the Tidle period expires first, the operation mode controller 16 enters the idle mode through the DREG-REQ (CMD) message exchange procedure with the base station 22 synchronized with the cell discovery procedure. Perform the entry.

However, if DL / UL traffic is generated after completing the network entry situation with the newly synchronized base station, the timer operation corresponding to the Tsleep and Tidle periods operated after the network entry is stopped and restarted. At this time, the operation mode controller 16 Update the previously reset Tidle period to the initially set Tidle value. Next, the operation of the terminal according to the embodiment of the present invention will be described.

5 is a flowchart illustrating an operation mode control in a terminal according to an embodiment of the present invention.

Referring to FIG. 5, the terminal 10 determines whether to enter a sleep mode in step 201. When the sleep mode is entered, the terminal 10 proceeds to step 203 to determine whether a listening window arrives. As described above, in the sleep mode, the terminal 10 alternately experiences a sleep window and a listening window. In the listening window, the terminal 10 may receive a downlink control message from the base station. When the listening window of the sleep mode arrives, the terminal 10 proceeds to step 205 to receive a downlink control message. The downlink control message contains a DL-MAP. The terminal 10 determines, in step 207, any one or a combination of the FN and the known base station ID information, which are expected to have any one or a combination of the FN and the base station ID information defined in the DL-MAP of the current downlink control message. By comparing with, it is determined whether the mobile station has moved to another base station area. The terminal 10 determines that any one or combination of the current DL-MAP FN and the base station ID information is different from any one or a combination of the expected FN and the known base station ID information, and moves to another base station area. Terminates the sleep mode and transitions to the normal mode.

Subsequently, the terminal 10 resets and activates Tidle in step 210 to activate Tsleep. Specifically, when the last sleep window time Tlastsleepwnd immediately before the transition in the normal mode is <= Tidle, the terminal 10 reflects Tlastsleepwnd in which the previous traffic does not occur and the previous traffic does not occur in the Tidle. Subtract Tlastsleepwnd you did not. The terminal 10 sets the Tidle period to Tlistenwnd when Tlastsleepwnd is> Tidle. Subsequently, the terminal 10 determines whether DL / UL traffic occurs during the Tsleep, reset Tidle period in step 211. That is, the terminal 10 determines whether Tsleep or Tidle times out. If DL / UL traffic occurs during the Tsleep, Reset Tidle period, Tsleep or Tidle cannot time out.

When the terminal 10 sleeps out the Tsleep or the Tidle, the terminal 10 proceeds to step 213 to enter a corresponding power saving mode by performing a procedure suitable for the timed out timer, that is, a message exchange procedure for entering a sleep mode or an idle mode. . Specifically, when the Tsleep is smaller than the Tidle, when the Tsleep period expires first, the terminal 10 sleeps through the MOB-SLP-REQ (RSP) message exchange procedure with the base station 22, which is synchronized through the cell discovery procedure. Perform the entry into. In addition, when the Tidle is smaller than the Tsleep, when the Tidle period expires first, the terminal 10 enters the idle mode through the DREG-REQ (CMD) message exchange procedure with the base station 22, which is synchronized through the cell discovery procedure. Perform.

On the other hand, when the DL 10 or the Tsleep or the Tidle does not time out and the DL / UL traffic occurs, the UE 10 proceeds to step 215 to stop and restart the Tsleep and Tidle timers operated after the network entry. Update the reset period of Tidle to the initially set Tidle value.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention not only provides an efficient implementation method for the terminal to transition from the sleep mode to the idle mode, but also facilitates the implementation procedure of the terminal by specifying an abstract entry time occurring in each mode. The present invention advantageously operates in idle mode for system resources and power saving when DL / UL traffic activity does not occur in a mobile terminal. Also, if DL / UL traffic activity does not occur in a mobile terminal, By using the advantage that the operation in the sleep mode for the incoming service is advantageous, the operation scenario for entering the sleep mode or idle mode from the sleep mode that the terminal enters through the normal mode because the traffic activity does not occur without introducing a separate implementation timer Presenting. As a result, the present invention makes it possible to implement a terminal capable of supporting sleep and idle modes through granting association and flexible concatenation for each mode that can be isolated while being mentioned in the specification.

 In addition, through the adaptive operation method of the Tidle period, the following effects can be achieved.

If the Tidle period is applied immediately after moving to another base station, the mobile station cannot enter the sleep mode. In addition, when the terminal moves at a high speed of more than 100 km / h in a cell having a radius of about 1 km, if the terminal frequently moves to another base station, the terminal enters Idle mode due to DL / UL traffic related to handoff and a long Tidle duration value. You can't. That is, despite the lack of data traffic, the handoff traffic must be moved to another base station before the Tidle period expires. Such frequent handoff situations occurring at high speeds not only accelerate the power consumption of the terminal but also cause unnecessary exchange of control messages. In order to prevent this, if the Tidle period is set short, the number of times the terminal enters Idle mode while the mobile station does not move is increased or when the mobile station moves, the mobile station can enter the idle mode but entering the sleep mode is not possible. It can't be done.

 However, if the Tidle period is adaptively applied according to the sleep mode operated in the previous base station, the moved base station can immediately apply the Tidle period reflecting the previous situation for the DL / UL traffic, and thus the terminal can be quickly applied. You can enter idle mode. Since the terminal entering Idle mode cancels the connection information through the DREG-REQ (CMD) message exchange procedure, the handoff procedure does not need to be performed even in the frequent handoff situation occurring at high speed. This induces the terminal to operate in an efficient low power mode, thereby extending the battery life of the terminal.

Claims (11)

A terminal for communicating with a base station in a wireless communication system, A base station change determination unit that determines whether the mobile station moves to another base station area based on the DL-MAP received in the listening window in the sleep mode; And an operation mode control unit for resetting the period for entering idle mode after canceling the sleep mode and transitioning to the normal mode when determining that the mobile station has moved to another base station area. The terminal of claim 1, wherein the operation mode controller sets the Tidle to a value obtained by subtracting the last sleep window interval from the existing Tidle when the last sleep window interval immediately before the transition to the normal mode is less than or equal to the existing Tidle period. . The terminal of claim 1, wherein the operation mode controller sets a Tidle to the listening window section when the last sleep window section immediately before the transition to the normal mode is larger than the existing Tidle period. 2. The base station change determining unit of claim 1, wherein the base station change determination unit comprises any one or a combination of a frame number (FN) and base station ID information defined in the DL-MAP, an expected FN, or a known base station ID information. The terminal characterized in that it determines whether it has moved to another base station area by comparing the. The method of claim 1, wherein the operation mode controller is further configured to enter a sleep mode or idle mode when any one of a Tsleep for entering a sleep mode or a Tidle for entering an idle mode times out after the transition to the normal mode. A terminal characterized in that performing an exchange procedure. The terminal of claim 5, wherein the operation mode control unit stops the timers and updates the Tsleep or Tidle period to an initial value when DL / UL traffic occurs after the transition to the normal mode. In the method of controlling the operation mode in the terminal communicating with the base station of the wireless communication system, Determining whether the user moves to another base station area based on the DL-MAP received from the listening window in the sleep mode; Determining that the mobile station has moved to another base station area, canceling the sleep mode and transitioning to the normal mode; And resetting the period Tidle for entering the idle mode. The method of claim 7, wherein the resetting of the Tidle is a process of setting the Tidle to a value obtained by subtracting the last sleep window interval from the existing Tidle when the last sleep window interval immediately before the transition to the normal mode is less than or equal to the existing Tidle period. How to feature. The method of claim 7, wherein the resetting of the Tidle is a process of setting the Tidle as the listening window section when the last sleep window section immediately before the transition to the normal mode is larger than the existing Tidle period. 10. The method of claim 7, wherein after transitioning to the normal mode, if any one of Tsleep for entering the sleep mode or Tidle for entering the idle mode times out, a message exchange procedure for entering the corresponding sleep mode or idle mode is performed. The method further comprises a process. 11. The method of claim 10, further comprising stopping the timers and updating the Tsleep or Tidle period to an initial value when DL / UL traffic occurs after the transition to the normal mode.

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