KR20070078279A - Mode switching method and mode switching control method applied to broadband wireless access system - Google Patents

Abstract

The present invention relates to a method for performing a mode switching by a mobile station in a broadband wireless access system supporting a sleep mode and an idle mode, the lane requesting a direct switch from the idle mode to the sleep mode. Mode switching method and mode comprising the step of transmitting a request message to the base station, in the ranging process, negotiating power consumption protection class parameters with the base station and performing a network re-entry process, switching to the sleep mode As a control method for switching, the mobile station in the idle mode can be directly transitioned to the sleep mode without going through the normal operation mode, there is an effect that can be performed efficiently.

Description

Mode switching method and mode switching control method applied to broadband wireless access system {Method for Mode Transtion and Control of Mode Transition in Broadband Wireless Access System}

1 is a flowchart illustrating a process of performing a sleep mode first class;

2 is a flowchart illustrating a process of performing a sleep mode second class;

3 is a flowchart illustrating a process of performing a sleep mode third class.

4 is an embodiment configuration diagram illustrating a paging group consisting of a plurality of base stations.

5 is a flowchart of a first embodiment showing a method of switching from an idle mode to a sleep mode;

6 is a flowchart of a second embodiment showing a method of switching from an idle mode to a sleep mode;

The present invention relates to a control method for mode switching and mode switching, and more particularly, to a method in which a mobile station in an idle mode switches directly to a sleep mode without going through a normal operation mode.

The broadband wireless access system supports sleep mode and idle mode in order to minimize power consumption of the mobile station.

First, the sleep mode is described as follows. The sleep mode is a repetition of a sleep interval and a listening interval, and by not transmitting or receiving a protocol data unit (PDU) during the sleep period, The power consumption of the mobile station can be reduced. The length of the sleep period and the listening period are determined by the values of the sleep window and the listening window, which may have different values depending on the characteristics of the traffic set in the corresponding mobile station. The mobile station performs periodic ranging when the window period ends.

Sleep mode includes the following three power saving classes. First, the first class is a class targeting a non-real-time variable rate (nrt-VR), which is a BE (Best Effort) having a characteristic of existing Internet traffic, or a non-real-time traffic of varying transmission rate. It is defined as an initial sleep window, a final window base, a final window exponent, a listening window, and a start frame number for sleep window. The size of the initial sleep window in the first class is doubled in the next frame.

The second class is for real-time variable rate (rt-VR), which is VoIP or real-time traffic with varying data rates. It is defined as three values: initial sleep window, listening window, and first frame number of sleep window. do. In the second class, the initially defined sleep window size remains constant until the sleep mode ends.

The third class is for management messages that need to be delivered periodically to mobile stations in sleep mode such as DCD / UCD, MOB_NBR-ADV, or data that must be delivered in multicast. Defined by frame number. That is, when the base station provides a service that the base station knows a schedule such as a multicast service, the mobile station can maintain the sleep state for each section in which the mobile station can maintain the sleep interval.

The sleep request message (MOB-SLP-REQ), the sleep response message (MOB-SLP-RSP), and the traffic notification message (MOB_TRF-IND) are used for information exchange for operation of each class of the sleep mode. Also, parameters optionally included in the ranging response message (RNG-RSP) are used.

Table 1 shows an example of part of the sleep request message (MOB-SLP-REQ).

Syntax Size (bits) Notes MOB_SLP-REQ_Message_format () {  Management message type = 50 8  Number of Classes 8 Number of power saving classes  For (i = 0; i <Number of Classes; i ++) {   Definition   Operation One   Power_Saving_Class_ID One    If (Operation = 1) { 6      Start_frame_number      Reserved 6     } 2    If (Definition = 1) {      Power_Saving_Class_type 2      Direction 2      Traffic_triggered_wakening_flag One      Reserved 3      Initial-sleep window 8      Listening-window 8      Final-sleep window base 10      Final-sleep window exponent 3      Number_of_Sleep_CIDs 3    For (i = 0; i <Number_of_Sleep_CIDs; i ++) {     CID 16       }     }   TLV encoded information variable  }

As shown in Table 1, the mobile station sends a sleep request message (MOB-SLP-REQ) including a sleep period and a listening period to the base station to request to switch to the sleep mode.

Table 2 shows an example of a part of the sleep response message (MOB-SLP-RSP).

Syntax Size (bits) Notes MOB_SLP-RSP_Message_format () {  Management message type = 51 8  Number of Class 8 Number of power saving classes  for (i = 0; i <Number_of_Classes; i ++) {   Length of data 7   Sleep Approved One   Definition One   Operation One   Power_Saving_Class_ID 6   if (Sleep Approved == 1) {    if (Operation = 1) {     Start_frame_number 6     Reserved 2    }    if (Definition = 1) {     Power_Saving_Class_Type 2     Direction 2     initial-sleep window 8     listening window 8     final-sleep window base 10     final-sleep window exponent 3     TRF-IND required One     Traffic_triggered_wakening_flag One     Reserved One

As shown in Table 2, the base station sends a sleep response message to the mobile station, including whether the mobile station is to go to sleep mode, sleep period, listening period and sleep ID.

Table 3 shows an example of a part of the traffic notification message (MOB_TRF-IND).

Syntax Size (bits) Notes MOB_TRF-IND_Message_format () {  Management message type = 52 8  FMT One  if (FMT == 0) {   SLPID Group Indication bit-map 32 Nth bit of SLPID-Group indication bit-map [MSB corresponds to N = 0 is allocated to SLPID Group that includes MS with SLPID values from N * 32 to N * 32 +31 Meaning of this bit 0: There is no traffic for all the 32 MS which belong to the SLPID-Group 1: There is traffic for at least one MS in SLPID-Group

As shown in Table 3, the mobile station receives the traffic notification message transmitted in a broadcast form at regular intervals to maintain the sleep mode or to exit the sleep mode and receive the downlink data or perform the ranging during the sleep period. Can be determined.

1 is a flowchart illustrating a process of performing a sleep mode first class. Referring to FIG. 1, when the mobile station intends to switch to the sleep mode, it transmits a sleep request message (MOB-SLP-REQ) to the base station (S11). The sleep request message includes information about an initial sleep interval, a final sleep interval, and a listening interval. Information about the first sleep section, the last sleep section and the listening section may be expressed in units of frames.

If the base station receiving the sleep request message allows the mobile station to switch to the sleep mode, it transmits a sleep response message (MOB-SLP-RSP) to the mobile station (S12). The sleep response message includes information on the first sleep section, the last sleep section, the listening section, and the transition time of the sleep mode. The first sleep section, the last sleep section and the listening section included in the sleep response message may be the same as or different from the first sleep section, the last sleep section and the listening section included in the sleep request message.

The mobile station receiving the sleep response message switches to the sleep state at the time of switching to the sleep mode and maintains the sleep state for the first sleep period. When the initial sleep interval expires, the listening interval begins. The mobile station receives a traffic notification message (MOB-TRF-IND) during the listening interval (S13) and checks whether there is downlink traffic to be transmitted to itself.

If there is no downlink traffic to be transmitted to the self, it is switched to the second sleep state and sleeps for the second sleep period. The size of the second sleep section is calculated from the size of the first sleep section. For example, twice the size of the first sleep section may be the size of the second sleep section. In addition, the size of the third sleep section may be calculated from the size of the second sleep section.

When the second sleep interval expires, the listening interval begins. The mobile station receives a traffic notification message (MOB-TRF-IND) during the listening interval (S14) and checks whether there is downlink traffic to be transmitted to the mobile station. As a result of the check, if there is downlink traffic to be transmitted to itself, the terminal ends the sleep mode, switches to the normal operation mode, and receives downlink traffic (S15).

On the other hand, if there is no downlink traffic to be transmitted to the third sleep section, the size of the sleep section is increased in the same manner as described above, and when the sleep section reaches the size of the last sleep section, the sleep section is no longer increased. And maintains the size of the last sleeping section.

The information on the last sleep section included in the sleep request message and the sleep response message may be represented by a final sleep window base and a last window exponent. In this case, the last sleep period can be calculated using Equation 1.

Final Sleep Window = Final Sleep Window Base * 2 ^{Final Window exponent}

When the mobile station needs to perform a handover in the sleep mode, for example, when entering a new base station area, the sleep mode is terminated and the handover process is performed.

As described above, when the mobile station once switched to the sleep mode state, if no downlink traffic has previously occurred in the sleep section, it is determined that there is a high possibility that no traffic occurs in the next sleep section, and the sleep section is increased. Through this process, power consumption of the mobile station can be minimized.

Sleep Mode In the second class, a mobile station in sleep mode operates according to a listening section and a sleeping section having a fixed size.

2 is a flowchart illustrating a process of performing a sleep mode second class.

Referring to FIG. 2, when the mobile station intends to switch to the sleep mode, the mobile station transmits a sleep request message (MOB-SLP-REQ) to the base station (S21). The sleep request message includes information about an initial sleep interval and an listening interval. Information about the first sleep section and the listening section may be expressed in units of frames.

If the base station receiving the sleep request message allows the mobile station to switch to the sleep mode, it transmits a sleep response message (MOB-SLP-RSP) to the mobile station (S12). The sleep response message includes information on the initial sleep section, the listening section and the sleep mode switching time. The first sleep section, the last sleep section and the listening section included in the sleep response message may be the same as or different from the first sleep section and the listening section included in the sleep request message.

The mobile station receiving the sleep response message switches to the sleep state at the time of switching to the sleep mode and maintains the sleep state for the first sleep period. During the listening section, the mobile station acquires synchronization to maintain up and down communication with the base station, and may receive downlink data from the base station during the listening section (S23).

When the listening section expires, the mobile station goes back to sleep and stays in sleep for the first sleep period. When the sleep interval expires, the radio is switched back to the listening interval, and downlink data can be received from the base station during the listening interval. On the other hand, if the mobile station wants to exit the sleep mode, the sleep mode end request is transmitted using the sleep request message (MOB-SLP-REQ) during the listening section (S24), or the user data is transmitted to the base station.

Sleep Mode In the third class, the mobile station performs sleep mode according to information transmitted through periodic ranging.

3 is a flowchart illustrating a process of performing a sleep mode third class.

Referring to FIG. 3, the mobile station periodically performs a ranging process to maintain uplink with the base station to obtain uplink transmission parameters. That is, the ranging request message (RNG-REQ) is transmitted to the base station (S31), and the ranging response message (RNG-RSP) is received from the base station (S32).

The ranging response message includes information on an uplink transmission parameter and a power saving class parameter, wherein the power saving class parameter includes a last sleep interval and a sleep mode switching time.

The mobile station receiving the ranging response message switches to the sleep mode at the time of switching to the sleep mode, and maintains the sleep state for the last sleep period. When the sleep period expires, communication with the base station is performed in the normal operation mode, and a ranging process is performed at a time for periodically performing ranging (S33, S34). During the ranging process, a ranging response message is received from the base station (S34). When the ranging message includes the power consumption prevention parameter, the sleep mode is performed based on the ranging response message.

Meanwhile, the idle mode will be described as follows. The broadband wireless access system supports idle mode to minimize power consumption of the mobile station. During the idle mode, the mobile station does not need to perform a handoff procedure when moving between base stations included in the same paging zone. Therefore, the mobile station does not have to transmit uplink information for the handover procedure, thereby reducing the power consumption.

The paging area is defined as an entire area that is handled by a plurality of base stations, called paging groups. Base stations included in the same paging area have the same value of paging period (Paging_Cycle) and paging offset (Paging_Offset).

The mobile station can request the base station to switch to idle mode, and the base station can transfer the paging area ID (paging-group ID), the corresponding paging period and paging offset, and the terminal can switch to the idle mode state.

During idle mode, the mobile station can determine whether to continue or exit idle mode through paging delivered in broadcast form from the base station at a predetermined paging period.

If there is traffic to be transmitted by the terminal in idle mode, the mobile station can exit idle mode at any time. On the other hand, when traffic to be delivered to the mobile station in idle mode occurs, the base station may cause the mobile station to exit idle mode through paging. In addition, when the mobile station in the idle mode does not receive the paging at a predetermined time due to moving to another paging area or losing synchronization, the mobile station terminates the idle mode. That is, the terminal entering the idle mode can freely move in the same paging area without performing the handover procedure by normally receiving the periodic paging unless there is information to be transmitted or received.

In order to configure one paging area, a paging group action message (paging-group-action), which is a backbone message transmitted between base stations, is used.

Table 4 shows an example of a paging-group-action.

Field Size Notes Message Type 8 bit Sender BS ID 48 bit Base station unique identifier (Same number as that broadcasted on the DL-MAP message) Target BS ID 48 bit Base station unique identifier (Same number as that broadcasted on the DL-MAP message) Time stamp 32 bit Number of miliseconds since midnight GMT (see to 0xTTTTTTTT to ignore) Action 4 bit 0-Assign target BS to paging groups 1-Remove targe BS from paging groups 2-Query (which paging groups target BS belongs to?) 3-Information (paging groups sender BS belongs to) Num records 4 bit Number of paging-group-ID records For (j = 0; j <Num Records; j ++) { Paging-group-ID 16 bit Paging group ID PAGING_CYCLE 16 bit Cycle in which the paging message is transmitted within the paging group PAGING OFFSET 8 bit MSS PAGING OFFSET parameter  } Security field TBD A means to authenticate this message CRC field 32 bit IEEE CRC-32

The backbone message is delivered to the base station. The backbone message may be used for the following four purposes depending on the content of the action field.

A target BS may be designated as a specific paging group (Action = 0). The receiving base station may be excluded from the specific paging group (Action = 1). It may ask which paging group the receiving base station belongs to (Action = 2). The transmitting base station (Sender BS) may indicate to which paging group (Action = 3).

Since one base station may belong to more than one paging area, the backbone message may include information about a plurality of paging groups. The backbone message allows the base stations to know the paging period and paging offset used in each paging area. The backbone message makes it possible to dynamically allocate base stations to paging groups.

4 is a diagram illustrating an embodiment of a paging group consisting of a plurality of base stations. As illustrated in FIG. 4, a plurality of base stations (BSs) supporting idle mode belong to a paging group to form a paging area.

Table 5 shows an example of a deregistration request message (DREG_REQ) used by the mobile station to switch to idle mode.

Syntax Size Notes DREG-REQ_Message_Format () {   Management Message Type = 29 8 bits 0x00 = SS de-registration request from BS and network 0x01 = request for MSS deregistration from Serving BS invitation of MSS paging Availability Mode 0x02-0xFF = reserved   De-registration Request Code 8 bits Only valid if De-Registration Request Code = 0x01   Paging Cycle Request 16 bits   TLV encoded parameter variable  }

The mobile station may request that the mobile station switch to the idle mode by setting the de-registration request code of the deregistration request message DREG_REQ to 0x01 and transmitting it to the base station. At this time, the administrator information of the mobile station which the base station desires to maintain after switching to the preferred paging period and idle mode can be transmitted to the base station.

Table 6 shows an example of TLV encoded parameters for the deregistration request message DREG_REQ.

  Name Type Length Value Paging Cycle Request 2 Requested cycle in which the paging message is trasnmitted within the paging group. Idle Mode Retain Information MSS request for Paging Controller retention of network re-entry related MAC management message MSS service and operational information to expedite future Network Re-entry from Idle Mode. For each Bit location, a value of '0' indicates the information associated with the specified MAC management message is not requested to be retained to be retained and managed. Bit # 0: Retain MSS service and operational information associated with SBC-REQ / RSP MAC management messages Bit # 1: Retain MSS service and operational information associated with PKM-REQ / RSP MAC management messages Bit # 2: Retain MSS service and operational information associated with REG-REQ / RSP MAC messages Bit # 3: Retain MSS service and operational information associated with Network Address Bit # 4: Retain MSS service and operational information associated with Time of Day Acquisition Bit # 5: Retain MSS service and operational information associated with TFTP MAC management messages Bit # 6: Retain MSS service and operational information with Full service (MAC state machines, CS classifier information, etc.)

The base station receiving the deregistration request message DREG_REQ may respond to a request of the mobile station through a deregistration command message DREG_CMD.

Table 7 shows an example of a deregistration command message (DREG_CMD).

Syntax Size Noets DREG-CMD_Message_Format () {   Management Message Type = 29 8 bits   Action code 8 bits   TLV encoded parameters variable  }

The base station allows the transition to the idle mode through the action code of the deregistration command (DREG_CMD) message (Action Code = 0x05), or requests the transition to the idle mode again after a certain time (Action Code = 0x06), it can be no longer requested to switch to idle mode until it sends a deregistration command message (Action Code = 0x07).

Table 8 shows an example of an operation code of the deregistration command message (DREG_CMD).

Action code Action 0x00 MSS shall immediately terminate service with BS and attempt network entry at another BS 0x01 MSS shall listen to the current BS but shall not transmit until an RES-CMD message or DREG_CMD with Action Code 0x00 is received 0x02 MSS shall listen to the current BS but only transmit on the Basic, Primary Management and Secondary Management Connections. 0x03 MSS shall return to normal operation and may transmit on any of its active connections. 0x04 MSS shall terminate current Normal Operation with the BS; the BS shall transmit this action code only in response to any MSS DREG-REQ 0x05 required MSS de-registration from Serving BS and request initiation of MSS Idle Mode 0x06 The MSS may retransmit the DREG-REQ message after the time duration (REQ-duration) provided in the message 0x07 The MSS shall not retransmit the DREG-REQ message and shall wait the DREG_CMD message 0x08-0xFF Reserved

The PLV (Type Length Value) item, which can optionally be included in the deregistration command message (DREG_CMD), allows the mobile station to maintain a paging group ID, paging cycle, and paging offset (Paging_Cycle). Paging_Offset) value can be passed.

Table 9 shows an example of the TLV parameters included in the deregistration command message DREG_CMD.

Name Type Length Value Paging Information 4 Bits 15: 0-PAGING_CYCLE-Cycle in which thepaging mes-sage is transmitted within the paging group Bits 23:16-PAGING OFFSET-Determines the frame within the cycle in which the paging message is transmitted. Must be smaller than PAGING CYCLE value Bits 31: 24- Paging-group-ID-ID of the paging group the MSS is assigned to REQ-duration One Waiting value for the DREG-REQ message retransmission (measured in frames) Paging Controller ID 6 This is a logical network identifier for the Serving BS or other network entity retaining MSS service and operational information and / or administering paging activity for the MSS while in IDLE Mode Idle Mode Retain Information One Idle Mode Retain Information is provided as part of this message is indicative only. Network Re-entry from Idle Mode process requirements may change at time of actual reentry. For each Bit location, a value of '0' indicates the information for the associated reentry management messages shall not be retained and managed, a value of '1' indicates the information for the associated re-entry management message shall be retained and managed Bit # 0: Retain MSS service and operational information associated with SBC-REQ / RSP MAC management messages Bit # 1: Retain MSS service and operational information associated with PKM-REQ / RSP MAC management messages Bit # 2: Retain MSS service and operational information associated with REG-REQ / RSP MAC management messages Bit # 3: Retain MSS service and operational information associated with Network Address Bit # 4: Retain MSS service and operational information associated with Time of Day Bit # 5: Retain MSS service and operational information associated with TFTP MAC management messages Bit # 6: Retain MSS service and operational information associated with Full service (MAC state machines, CS classifier information , etc)

As described above, the deregistration command message DREG_CMD includes paging information as a TLV parameter, manager member information of the mobile station maintained by the base station after the mobile station switches to idle mode, and a paging control station identifier. Information retained by the base station when the mobile station transitions to idle mode is omitted in the network registration procedure if the idle mode mobile station exits idle mode or performs a location update procedure in the future. This is to enable fast network registration and location update of the mobile station.

Table 10 shows an example of the paging advertisement message (MOB-PAG-ADV).

Syntax Size Notes MOB_PAG-ADV_Message_Format () {   Management Message Type = 62 8bits   Num_Paging Group IDs 8bits Number of Paging Group IDs in this message   For (i = 0; i <Num_Paging_Group_IDs; i ++) {     Paging Group ID 8bits    }   For (j = 0; j <Num_MACs; j ++) { Number of MSS MAC Addresses in message can be determined from the length of the message (found in the generic     MSS MAC Address hash 24bits     Action code 2bitss Paging action instruction to MSS 00 = No Action Required 01 = Performing Ranging to establish location and acknowledge message 10 = Enter Network 11 = reserved     Reserved 6bits    }   TLV Encoded Information variable TLV specific   reserved variable Padding bits to ensure octet aligned   }

The mobile station may maintain the idle mode or terminate the idle mode by receiving the paging advertisement message (MOB-PAG-ADV) at a paging offset at a predetermined paging period. The mobile station in the idle mode determines whether to end the idle mode, perform a location update procedure, or maintain the idle mode by receiving a paging advertisement message (MOB-PAG-ADV) periodically transmitted from the base station.

Among cases where exiting the idle mode and returning to the normal mode is necessary, the service may be available even in the sleep mode. However, even in this case, there is a problem that communication is inefficiently performed by returning to the sleep mode after returning from the idle mode.

It is an object of the present invention to provide a method in which an idle mobile station can switch directly to a sleep mode according to a type of traffic service.

The present invention for achieving the above object in the broadband wireless access system that supports the sleep mode (Sleep Mode) and idle mode (Idle Mode), in the method for the mobile station to perform the mode switching, from the idle mode to the sleep mode Transmitting a ranging request message to the base station requesting direct conversion of the mobile station; negotiating power consumption protection class parameters with the base station and performing a network re-entry process in the ranging process; It is made to include.

In addition, the present invention is a method for controlling the mode switching of the mobile station by the base station in a broadband wireless access system that supports the sleep mode (Sleep Mode) and idle mode (Idle Mode), traffic is generated in the mobile station in the idle mode Transmitting a paging advertisement message indicating that the mobile station is in an idle mode, and receiving a ranging request message including a request for direct switching to the sleep mode and power consumption prevention class parameters; And in the ranging process, controlling the mobile station to switch to a power consumption protection class corresponding to the characteristic of the traffic.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The following describes a method of initiating idle mode. When initiated by the mobile station, the mobile station sends a deregistration request message (DREG_REQ) to the base station, operates the timer T45, and then deregistration command message (DREG_CMD) until the timer set time out. If it is not received, the deregistration request message DREG_REQ may be retransmitted to the base station up to a predetermined number of times (DREG Request Retry Count). On the other hand, if the deregistration request message DREG_REQ is transmitted to the base station for the predetermined number of times, but fails to receive the deregistration command message DREG_CMD, the idle mode MAC is re-initialized again. The base station receives the deregistration request message (DREG_REQ) and transmits a deregistration command message (DREG_CMD) to operate a management resource holding timer (Managemet_Resource_Holding_Timer (T46)).

Meanwhile, a method of starting the idle mode by the base station is as follows. The base station transmits by setting the operation code corresponding to the REQ-duration TLV of the deregistration command message DREG_CMD to 0x05. If the deregistration request message DREG_REQ is not received from the mobile station until the management resource holding timer (Managemet_Resource_Holding_Timer (T46)) expires, the base station sends the deregistration command message DREG_CMD to the mobile station again. The deregistration command message DREG_CMD may be retransmitted up to a predetermined number of times (DREG Command Retry Count). When the base station receives the deregistration command message DREG_CMD in the REQ-duration and transmits the DREG-REQ, the mobile station enters an idle mode state.

In general, in the broadband wireless access system, the mobile station in the idle mode is changed to the normal operation mode when the following cases occur. That is, when uplink traffic occurs in the mobile station or downlink traffic occurs in the base station, the mobile station returns to the normal operation mode. In addition, when the mobile station does not receive the paging advertisement message due to loss of synchronization with the serving BS, the mobile station returns to the normal operation mode.

5 is a flowchart of a first embodiment illustrating a method of switching from an idle mode to a sleep mode. Referring to FIG. 5, the mobile station may terminate the idle mode if necessary, such as when traffic to be transmitted on the uplink occurs. In this case, the mobile station can inform the base station that uplink traffic has occurred and terminate the idle mode. When the traffic to be transmitted in the uplink occurs, the mobile station terminates the idle mode and receives the uplink radio resource and transmits a ranging request message (RNG-REQ) to the base station to transmit information in the uplink (S51). At this time, the mobile station informs the base station that the mobile station will transition from the idle mode to the sleep mode through the ranging request message (RNG-REQ). At this time, by setting bit 2 of the 'Ranging Purpose Indication' field of the ranging request message (RNG-REQ) to '1', it can be notified that the mobile station will transition from the idle mode to the sleep mode.

Table 11 shows an example of ranging request message (RNG-REQ).

Name Type (1 byte) Length Value (variable-length) Serving BS ID 5 6 Ranging Purpose Indication 6 One Bit # 2: MS => Direct Sleep Mode HO ID 7 One Paging Controller ID 9 6 MAC Hash Skip Threshold 10 2 Power_Saving_Class_Parameters 21 Variable Power down indicator 8 One Enabled-Action-Triggered 11 One Requested downlink repetition coding level 12 One

Meanwhile, the mobile station sets power_saving_class_parameters values of the ranging request message (RNG-REQ) according to the type of traffic and transmits them to the base station.

Table 12 shows an example of the power consumption protection class parameters.

Name Type (1 byte) Length Value (variable-length) Flags One One Bit 0: Definition 1 = Definition of Power Saving Class present Bit 1: Operation (RNG-RSP only) 0 = Deactivation of power saving class 1 = Activation of power saving class (for type 1 and 2 only) Bit 2: TRF-IND_Required For Power Saving Class Type I only 1 = BS shall transmit at least on TRF-IND message during each listening window of the power saving class. This bit shall be set to 0 for another types Bit 3-7: reserved Power_Saving_Class_ID 2 One Power_Saving_Class_Type 3 - Start_frame_number 4 One Initial-sleep window 5 One listening window 6 One Final-sleep window base 7 One Final-sleep window exponent 8 One SLPID 9 One CID 10 2 Direction 11 One

On the other hand, the base station transmits an MSS info request to the backbone (backbone) in order to know the information that can be omitted in the ranging process with the mobile station from a neighboring base station or a paging controller (S52), In step S53, an MSS info response is received from the neighbor BS or the paging controller. When the ranging process is performed with the mobile station, the mobile station transitions to the sleep mode.

6 is a flowchart of a second embodiment illustrating a method of switching from an idle mode to a sleep mode. Referring to FIG. 6, when downlink traffic occurs from a base station to a mobile station in a sleep mode state, a paging advertisement message (MOB-PAG-ADV) for notifying of this may be transmitted (S61). For example, the base station may set an action code of the paging advertisement message (MOB-PAG-ADV) to 0b10 and transmit it to the mobile station.

The mobile station receiving the paging advertisement message (MOB-PAG-ADV) including the operation code performs a network reentry process. In this case, a ranging process is performed to reenter the network. In the ranging process, the mobile station may transmit a ranging request message (RNG-REQ) including the power consumption prevention class parameter as described above (S62). When the power consumption prevention class parameters are negotiated during the ranging process and the registration procedure is performed with the base station, the mobile station transitions to the sleep mode. At this time, in the case of services corresponding to power consumption protection classes 2 and 3 (RT-VR service or multicast service such as VoIP), power consumption protection class 1 should also be activated. That is, in the case of the power consumption prevention class 1, the BE (Best Effort) service is supported. Since the BE service characteristics cannot predict when traffic will occur in advance, when the power consumption prevention classes 2 and 3 are activated, power consumption prevention is prevented. Class 1 must also be activated.

The mobile station can directly transition to the sleep mode to which the power protection consumption class according to the service type is directly applied without going through the normal operation mode in the idle mode, thereby preventing unnecessary power consumption.

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

According to the present invention, when the mobile station in the idle mode is required, the mobile station can directly transition to the sleep mode without going through the normal operation mode, thereby effectively communicating.

Claims (8)

In a broadband wireless access system supporting a sleep mode and an idle mode, a method for a mobile station to perform mode switching, Transmitting a ranging request message to the base station requesting direct switching from the idle mode to the sleep mode; Negotiating power consumption prevention class parameters with the base station in a ranging process; And Performing network reentry process to switch to sleep mode Mode switching method comprising a. The method of claim 1, And requesting a direct switch from the idle mode to the sleep mode by using the 'Ranging Purpose Indication' field of the ranging request message. The method of claim 2, And setting bit 2 of the 'Ranging Purpose Indication' field to '1' to request a direct switch from the idle mode to the sleep mode. The method of claim 1, And receiving a paging advertisement message indicating that traffic has occurred from the base station. The method of claim 4, wherein The mode code of the paging advertisement message (Action Code) is characterized in that the mode is set to 0b10. The method of claim 5, And the mobile station switches to a sleep mode of a class corresponding to the downlink traffic characteristic of the base station. In a broadband wireless access system supporting sleep mode and idle mode, a method of controlling a mode switching of a mobile station by a base station, Sending a paging advertisement message to the mobile station in idle mode indicating that traffic has occurred; Receiving, by the mobile station in idle mode, a ranging request message including a request for direct switching to sleep mode and power consumption prevention class parameters; And In a ranging process, controlling the mobile station to switch to a power consumption prevention class corresponding to a characteristic of the traffic; Mode switching control method comprising a. The method of claim 7, wherein Transmitting a mobile station information request message to a neighboring base station or a paging controller to obtain information that can be omitted in the ranging process with the mobile station; And Receiving, from the neighbor base station or the paging controller, a mobile station information response message including information that can be omitted in the ranging process; And the ranging process is performed using the mobile station information response message.

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