KR20060045108A - Method of downlink traffic indication in power saving mode in broadband radio access system - Google Patents

Abstract

The present invention relates to a power saving mode for minimizing power consumption of a mobile subscriber station (MSS) in a broadband wireless access system based on an IEEE802.16e system. If there is a downlink traffic (downlink traffic) to be delivered to a terminal that exists in a timely manner.

Broadband, Wireless Access, Mobile Terminal, Power Consumption Prevention Mode, Base Station, TLV

Description

Method of downlink traffic indication in power saving mode in broadband radio access system

1 is a procedure flow diagram illustrating the operation of power saving class 1 in the prior art.

Figure 2 is a procedure flow diagram illustrating the operation of power saving class 2 in the prior art.

3 is a process flow diagram illustrating the operation of power saving class 3 in the prior art.

4 is a procedure flow diagram illustrating an operation of a mobile terminal receiving data from a base station through a multicast connection in the prior art operating in power saving class 3 to reduce power consumption.

FIG. 5 is a flowchart illustrating an operation of a power consumption prevention mode of a mobile terminal having multiple service types activated in the prior art. FIG.

6 is a view for explaining the operation of the preferred embodiment of the present invention.

The present invention relates to a power saving mode for minimizing power consumption of a mobile subscriber station (MSS) in a broadband wireless access system based on an IEEE802.16e system. In particular, the present invention relates to a power saving mode. If there is a downlink traffic (downlink traffic) to be delivered to a terminal that exists in a timely manner.

A broadband wireless access system based on the IEEE802.16e system supports a power saving mode for minimizing power consumption of a mobile terminal. In the power consumption prevention mode, the operation of the mobile terminal consists of repetition of the sleep interval and listening interval, and the sleep determined by the values of the sleep window and the listening window, respectively. The length of the period and the listening period have different values depending on the characteristics of the traffic set in the mobile station. Accordingly, the mobile terminal may have three types of power saving class according to the currently set traffic characteristics.

1.Power Saving Mode Class of type 1

2. Power Saving Mode Class of type 2

3. Power Saving Mode Class of type 3

Class 1 is a class that targets non-real-time variable rate (nrt-VR), which is BE (Best Effort) or non-real-time traffic whose transmission rate is changed, and has an initial sleep window. It is defined as the final window base, the final window exponent, the listening window, and the start frame number for sleep window.                         

Class 2 is a class for rt-VR (real-time variable rate), which is a real-time traffic of varying VoIP or transmission rate, and is defined by three values of initial sleep window, listening window, and initial frame number of sleep window.

Class 3 is for management messages that must be delivered periodically to mobile terminals in power saving mode, such as DCD / UCD, MOB_NBR-ADV, or data that must be delivered in multicast. Last Window Base, Last Window Index, Sleep Window It is defined as the first frame number of.

In order to exchange information for the operation of each class of the power consumption prevention mode defined above, the parameters optionally included in the ranging response message (RNG-RSP), which is one of the following three messages and existing messages, are basically used.

Table 1 shows an example of the MAC management message that the mobile station transmits to the service base station for the sleep mode request including the sleep period and the listening period.

Syntax Size Notes MOB SLP-REQ Message Format () {  Management message type = 51 8 bits  for (i = 0; i <Number of Classses; i ++) {     Operation 1 bits     Power Saving Class ID 6 bits     if (Operation = 1) {        Start frame number 6 bits        TRF-IND Required 1 bit        Reserved 2 bits     }     if (Definition = 1) { 2 bits        Power Saving Class Type 2 bits        Direcion 8 bits        initial-sleep window 8 bits        listening window 10 bits        final-sleep window base 3 bits        final-sleep window exponent 3 bits        Number if CIDs        for (i = 0; i <Number if CIDs; i ++) { 16 bits           CID        }      }   }

Table 2 shows an example of the MAC management message that the service base station delivers sleep mode related information such as whether to allow the sleep mode, the sleep period, the listening period, and the sleep ID through the sleep response.

Syntax Size Notes  MOB SLP-RSP Message Format () {   Management message type = 51 8 bits   for (i = 0; i <Number of Classes; i ++) {      Definition 1 bit      Operation 1 bit      Power Saving Class ID 6 bits      If (Operation = 1) {         Start frame number 6 bits         TRF-IND Required 1 bit         Reserved 1 bit      }      If (Definition = 1) {         Power Saving Class Type 2 bits         Direction 2 bits         initial-sleep window 8 bits         listening window 8 bits         final-sleep window base 10 bits         final-sleep window exponent 3 bits         SLPID 10 bits         Reserved 2 bits         Number of CIDs 3 bits         for (i = 0; i <number of CIDs; i ++) {            CID 16 bits         }       }       If (SHO or FBSS capability enabled) { 1 bit         Maintain Active Set and Anchor BS ID         If (Active Set and Anchor BS ID maintained) { 3 bits            SHO / FBSS duration (s)         }       }       Padding Variable If needed  }

Table 3 shows an example of a broadcast type traffic notification message transmitted at regular intervals. The terminal in the sleep mode receives the traffic notification message during the listening period, and keeps the sleep mode or terminates the sleep mode. Receive or decide whether to perform ranging during sleep.                         

Table 4 is an example of a power saving class parameter included in the ranging response message, which is a variable length parameter that can be selectively and combined if necessary. That is, this parameter may be referred to as a compound parameter in which a parameter consisting of various variables below may be selectively included in one parameter defined as type 21 as needed.

Name Type (1 byte) Length Value (Variable-length)  Power_Saving_Class_Parameters 21 variable  Compound TLV to specify Power Saving Class operation                                                      斐 operation operation  Flags One Bit 0: Definition 1 = Definition of Power Saving Class present Bit 1: Operation 1 = Activation of Power Saving Class 0 = Deactivation of Power Sacing Class (for types 1 and 2 only) Bit 2: TRF-IND Required For Power Saving Class Type 1 only 1 = BS shall transmit at least one TRF-IND message during each listening window of the Power Saving Class.This bit shall be set to 0 for another types Bits 3-7 reserved  Power saving class id  Assigned Power Saving Class identifier  Power Saving Class Type Power Saving Class Type as specified in 6.3.2.3  Start frame number Start frame number for first sleep window  initial-sleep window initial-sleep window  listening window Assigned Duration of MSS listening interval (measured in frames)  final-sleep window base Assigned final value for the sleep interval (measureed in frames) -base  final-sleep window exponent Assigned final value for the sleep interval (measured in frames) -exponent  SLPID A number assigned by the BS whenever an MSS is instructed to enter sleep-mode

CID                                              CID of connection to be included into the Power Saving Class. There may be several TLVs of this type in a single compound Power Saving Class Parameters TLV Direction                                                                                                One Direction for management connection which is added to PowerSaving Class

The operation of each class will be described in detail in the following operation description of the prior art device.

1 illustrates a case in which the power consumption prevention mode class 1 requests the mobile station to switch to the power consumption prevention mode and maintains the downlink traffic to the mobile station to terminate the power consumption prevention mode. The operation is shown. Each operation is as follows.

The mobile terminal sets the initial sleep window, the last sleep window, and the listen window to the base station in the sleep request message shown in Table 1, and requests the mobile station to switch to the power saving mode.

When the base station allows the mobile terminal to switch to the power saving mode, it transmits the sleep response message shown in Table 2 that sets the initial sleep window, the last sleep window, the listening window, and the first frame number of the sleep window. do.

The mobile terminal maintains the same sleep period as the initial sleep window when the start time of switching to the power saving mode is reached.

When the mobile terminal expires, it receives the traffic notification message shown in Table 3 from the base station during the following listening period, and when there is no downlink traffic directed to itself (negative indication), it prevents power consumption for twice as long as the initial sleep window. Keep the mode.

Through the above formula (the next sleep window is set to double the previous sleep window), the sleep period continues to increase, and the final sleep window size is the final window basis determined by the sleep response message in Table 2. Sleep window base) and final window index (final window exponent) is set as shown in Equation 1 below.

final sleep window = final sleep window base * 2 ^{final window exponent}

If the mobile station receives a traffic indication message indicating that there is downlink traffic directed to itself during the listening period, the power saving mode is terminated.

Hereinafter, the power consumption prevention class 2 will be described.

FIG. 2 is a terminal using an unsolicited grant service (UGS) service that provides one fixed data rate or a real time variable service (RT-VR) service that provides one real-time variable data rate. It is a figure which shows the description to make. Each operation procedure is as follows.

(1) The mobile station transmits the sleep request message shown in Table 1 to the base station and requests to switch to power saving mode class 2.

(2) The base station receiving the sleep request message allows the terminal to switch to the power consumption prevention mode class 2 by setting a fixed sleep period, a listening period, and a power saving mode switching time point in the sleep response message.

(3) When it is time to change the power saving mode, the mobile terminal maintains the power consumption protection mode for the sleep period.

(4) When the sleep period expires, the mobile terminal synchronizes to maintain up and down communication with the base station, and enables downlink data reception and uplink data transmission from the base station to the base station during the listening period.

(5) When the listening period expires, the mobile terminal maintains the power consumption prevention mode for the sleep period, thereby preventing power consumption. Thereafter, the mobile terminal operates in the power consumption prevention mode class 2 by repeating the processes (4) and (5).

(6) If the mobile terminal wants to end the power saving mode class 2, it sets the power saving prevention termination in the sleep request message during the listening period and transmits it to the base station or transmits the user data to the base station during the sleep period.

(7) After the power consumption prevention mode class 2 is terminated, the mobile terminal operates normally.

Hereinafter will be described the operation of the power consumption prevention class 3 associated with performing the ranging procedure.

FIG. 3 illustrates an operation description of power consumption prevention class 3 for reducing power consumption while the mobile station performs periodic ranging for uplink communication with the base station and validity update of the terminal.                         

(1) When the mobile station turns on the power and performs a registration procedure in the network to switch to a normal operation state, the mobile station periodically performs a ranging procedure to maintain uplink communication with the base station, thereby obtaining an appropriate uplink transmission parameter.

(2) When the periodic ranging time is reached, the mobile station delivers the ranging request message to the base station.

(3) The base station receiving the ranging request message from the mobile station sets and transmits the adjustment value of the uplink transmission parameter to the ranging response message to the corresponding terminal, and at this time, the power consumption prevention class parameters (sleep period and start) shown in Table 4 below. Point of view, etc.), the mobile terminal can be switched to Class 3 of the power saving mode.

 (4) The mobile terminal, which receives the switching to the power saving mode through the ranging response, maintains the power saving mode for the sleep period when the power saving mode is changed.

(5) When the sleep period expires, the mobile station maintains a state in which communication with the base station is possible, and when it is time to perform periodic ranging, the mobile station performs periodic ranging with the base station. The mobile station receives the ranging response message from the base station to obtain parameter values and power consumption prevention parameters for uplink communication.

(6) When the mobile terminal receives the power consumption protection parameter, the mobile terminal maintains the power consumption protection mode during the sleep period when the power consumption switching time is reached.

(7) Repeat step (5).

(8) Repeat step (6).                         

The following is a description of the power consumption prevention class 3 operation of a mobile terminal in which a multicast connection is maintained.

FIG. 4 shows an operation description in which a mobile terminal receiving data from a base station through a multicast connection operates in a power saving class 3 for reducing power consumption.

(1) The base station transmits a sleep response message to the mobile station, and causes the mobile station to switch to the power saving mode class 3.

(2) The mobile terminal receiving the sleep response message maintains the power saving mode for the sleep period when the start frame of the power saving mode is reached.

(3) When the sleep period expires, the communication with the base station is maintained and the data transmitted from the base station is received through the multicast connection.

(4) When the base station transmits all data transmissions while the multicast connection is maintained, the base station delivers a sleep response message so that the mobile station can prevent power consumption until the next multicast data transmission. Switch to power saving mode class 3.

(5) The mobile terminal which receives the sleep response message maintains the power consumption protection mode during the sleep period when it is time to switch to the power saving mode.

(6) Repeat steps (3), (4) and (5).

As described above, in the broadband wireless access system, in order to reduce power consumption of the mobile terminal, a power consumption prevention class is supported for each connection according to the service type.                         

FIG. 5 is a diagram illustrating an operation of a power consumption prevention mode of a mobile terminal in which several power consumption protection classes are activated.

As described above, the mobile terminal in which the various power consumption prevention classes are activated temporarily disables up and down communication with the base station in order to prevent power consumption during periods in which sleep periods overlap each other.

As described above, in the prior art, the mobile terminal and the base station operate the power consumption prevention mode for each connection according to the service type. A mobile terminal with a connection enabled to deliver data of Best Service or Real Time Variable Rate operates by activating Power Consumption Prevention Class 1 to reduce power consumption. Has been made in the configuration and operation of the prior art.

The following shows the conditions for deactivation of the power saving class 1 defined in the prior art.

(1) The mobile terminal receives user data from the base station through the connection during the listening period.

(2) When the mobile station requests the base station to allocate bandwidth for the connection

(3) When the mobile station is instructed by the base station that there is downlink data buffered through the traffic indication message

(4) When the mobile station does not receive the traffic indication message during the listening period

As above, the mobile terminal activates the power consumption prevention class in order to reduce power consumption during the sleep period, and checks the existence of the downlink traffic directed to the user through the traffic indication message when the listening period is reached, to activate the power consumption prevention class. Determine whether to deactivate.

However, in the power consumption prevention class 1, the sleep period is exponentially increased, and in the case where the sleep period is very large, even if downlink traffic to the terminal occurs, the downtime traffic can be notified during the listening period when the sleep period expires. Problems arise. In this case, the base station has a problem in that the downlink traffic to the terminal for a long time to buffer or discard the data.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is the sleep used in the power consumption protection class 3, when downlink traffic occurs in the connection corresponding to the power consumption protection class 1 By notifying the user through a response message or a ranging response message, a method for downlink traffic notification in a power saving mode of a broadband wireless access system in which power consumption protection class 1 is deactivated and a mobile station can receive downlink traffic can be provided. It aims to do it.

When the downlink data for the power saving class 1 occurs during the sleep period of the terminal, the base station can notify the traffic occurrence through the ranging response message of the power saving class 3 as well as the traffic indication message transmitted during the listening period. In order to ensure that the CID and the disable bit setting for the power consumption protection class 1 is included in the ranging response message in the form of a TLV parameter as follows.

Name Type (1 byte) Length Value (Variable-Length) Power_Saving_Class_Parameters 21 Variable Compound TLV to specify Power Saving Class operation Flags One Bit 0: Definition 1 = Definition of Power Saving Class Present Bit 1: Operation 1 = Activation of Power Savings Class 0 = Deactivation of Power Saving Class (for types 1 and 2 only) Bit 2: TRF-IND_Required For Power Saving Class Type 1 only. 1 = BS shall transmit at least one TRF-IND message during each listening window of the Power Saving Class. This bit shall be set to 0 for another types Bits 3-7: reserved Power_Saving_Class_ID One Assigned Power Saving Class identifier Power_Saving_Class_Type One Power Saving Class Type as specified in 6.3.2.3 SLPID One A number assigned by the BS whenever an MSS is instructed to enter sleep-mode CID CID of connection to be included into the Power Saving Class. There may be several TLVs of this type in a single compound Power_Saving_Class_Parameters TLV Direction One Direction for management connection which is added to Power Saving Class

In addition, if the mobile station is operating in power saving mode with power saving class 3 for a multicast connection, the base station can inform the mobile station of the downlink traffic for the power saving class 1 connection through a sleep response message. have.

Syntax Size Notes MOB_SLP-RSP_Message_Format () {  Management message type = 51 8bits  for (i = 0; i <Number_of_Classes; i ++) {  Definition 1 bit  Operation 1bits Set to 0  Power_Saving_Class_ID 6bits  If (Operation = 1) {    Start_frame_number 6bits    TRF-IND_Required 1 bit    Reserved 1 bit  }  If (Definition = 1) {    Power_Saving_Class_Type 2 bits    Direction 2 bits    initial-sleep window 8bits    listening window 8bits    final-sleep window base 10bits    final-sleep window exponent 3bits    SLPID 10bits    Reserved 2 bits    Number_of_CIDs 3bits    for (i = 0; i <Number_of_CIDs; i ++) {     CID 16 bits Set the CID that the traffic came from    }  }  If (SHO or FBSS capability enabled) { 1 bit    Maintain Active Set and Anchor BS ID     If (Active Set and Anchor BS ID maintained { 3bits       SHO / FBSS duration (s)    }   }   Padding Variable If needed  }

When the downlink traffic for the power consumption prevention class 1 connection is informed to the mobile terminal through the sleep response message as described above, the operation bit setting value 0 and the corresponding CID are set to indicate the deactivation and transmitted to the mobile terminal.

FIG. 6 shows power consumption prevention class 1 by informing a corresponding terminal through a ranging response message when downlink traffic for power consumption prevention class 1 is generated to a mobile terminal operating in power consumption prevention class 1 and power consumption prevention class 3; It is a figure which shows operation to deactivate.                     

As shown in FIG. 6, when the mobile terminal is instructed to have no down traffic during the listening period as in the conventional operation in the power consumption prevention class 1, the mobile station performs an operation for preventing power consumption while exponentially increasing the sleep period. . If downlink traffic occurs during the power saving class 1 sleep period, as shown in the figure above, include the TLV to terminate the power saving mode for the corresponding connection of class 1 in the power saving class 3 ranging response message. Informing this, the mobile station terminates the power saving mode for the connection, and receives downlink traffic from the base station.

FIG. 7 shows the mobile terminal with power consumption prevention class 1 and power consumption prevention class 2 activated by setting a sleep response message as shown in Table 6 when the downlink data for the power consumption prevention class 1 is generated. A diagram showing a method of deactivating anti-consumption class 1.

As shown in FIG. 7, the mobile terminal performs an operation for preventing power consumption by exponentially increasing the sleep period when it is indicated that there is no downward traffic during the listening period as in the conventional operation in the power consumption prevention class 1. As shown in FIG. . If downlink traffic occurs during the power saving prevention class 1 sleep period as shown in the above figure, the sleep response message as shown in Table 6 proposed by the present invention is transmitted to the corresponding terminal during the listening period of the power saving prevention class 2. By doing so, it informs the end of the power saving mode for the corresponding connection of the class 1, the mobile terminal ends the power saving mode for the connection, and receives the downlink traffic from the base station.

FIG. 8 illustrates the sleep response message configuration shown in Table 6 proposed by the present invention when downlink data is generated for power consumption prevention class 1 to a mobile terminal in which power consumption protection class 1 and power consumption protection class 3 for multicast connection are activated. By showing this through, a diagram showing a method of deactivating the power consumption protection class 1.

As shown in FIG. 8, when the mobile terminal is instructed to have no downlink traffic during the listening period as in the conventional operation in the power consumption prevention class 1, the mobile station performs an operation for preventing power consumption while exponentially increasing the sleep period. . If down traffic occurs during the sleep period of power saving class 1 as shown in the above figure, the sleep period of power saving class 3 expires and the sleep response message of power saving class 3 during normal operation is proposed in the present invention. By transmitting a sleep response message as shown in Table 6 to the terminal, to inform the end of the power saving mode for the connection of the class 1, the mobile terminal terminates the power saving mode for the connection, down from the base station Receive traffic.

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

According to the present invention, it is possible to inform the ranging response message and the sleep response message used in the power consumption prevention class 2, 3 for downlink traffic generation for the power consumption prevention class 1, the corresponding terminal prevents power consumption in a timely manner Disable Class 1 and allow downstream data to be received. As a result, the base station reduces the load of the base station by not buffering the downlink data for a long time and prevents the base station from discarding the data, thereby preventing the terminal from data loss.

Claims (1)

In a broadband wireless access system, If a downlink message for a power saving class 1 for a mobile subscriber station (MSS) in a power saving mode is generated, a ranging response message of the power saving class 3 is transmitted to the mobile terminal. Downlink traffic notification method in the power consumption prevention mode of the broadband wireless access system, characterized in that the traffic generation.

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