KR101356887B1 - Apparatus and method for updating slpid of a terminal operating in sleep mode in a broadband wireless communication system - Google Patents

Abstract

The present disclosure provides a method of operating a base station for supporting a sleep mode in a broadband wireless communication system, the method comprising: transmitting a sleep response message including sleep identification information to a terminal in a sleep mode entry process; When the sleep identification information is updated, transmitting a traffic indication message including the updated sleep identification information to the terminal in a listening window of a sleep mode; Receiving a traffic indication request message from the terminal after the listening period; And transmitting a traffic indication response message including the updated sleep identification information to the terminal.

Description

A method and apparatus for updating a sleep identifier of a sleep mode terminal in a broadband wireless communication system {APPARATUS AND METHOD FOR UPDATING SLPID OF A TERMINAL OPERATING IN SLEEP MODE IN A BROADBAND WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates to a sleep identifier update in a broadband wireless communication system, and more particularly, to a method and an apparatus for updating a sleep identifier of a sleep mode terminal when a traffic indication message including an updated sleep identifier is not received.

Since the broadband wireless mobile communication system considers the mobility of the terminal, the power consumption problem of the terminal is a significant factor compared to other systems. As a method for minimizing the power consumption of the terminal, a sleep mode operation between the terminal and the base station has been proposed.

In the sleep mode operation, when the terminal communicates with the base station in the active mode and there is no traffic to transmit or receive with the base station, the terminal requests to enter the sleep mode and receives a response from the base station to enter the sleep mode. Change the state.

Upon entering the sleep mode, the UE receives a message indicating whether there is traffic transmitted from the base station during the sleep mode listening window, and receives a negative indication that there is no traffic. Judging that this does not exist.

In addition, when receiving a positive indication from the base station during the listening window, the terminal determines that there is data traffic transmitted in the downlink to initialize the current sleep mode period. In this case, the type of data traffic that the terminal can receive may be a real-time or non-real-time service, and packet data transmitted and received by the terminal when a non-real time service such as a short message is received. Has aperiodicity, and when receiving a real time service such as Voice on IP (VoIP), packet data transmitted and received by the UE has a periodicity.

1 is a flowchart sequentially illustrating a general sleep mode operation.

When the terminal communicates with the base station in normal or active mode and there is no more traffic to transmit and receive with the base station, the terminal transmits a Sleep-Request (SLP-REQ) message to enter the sleep mode to the base station (S101). ).

The base station receives the SLP-REQ message from the terminal and transmits a SLP-RSP (Sleep-Response) message to the terminal in response (S102).

The SLP-RSP message includes sleep mode operation parameters such as a sleep cycle and a listening window for a sleep mode operation of the terminal. The listening section used below has the same meaning as the listening window and the sleep section has the same meaning as the sleep window.

In some cases, even if there is no sleep mode entry request message (S101) of the terminal, the base station may directly transmit an unsolicited SLP-RSP message to the terminal to instruct the terminal to enter the sleep mode.

The terminal receiving the SLP-RSP message from the base station performs a sleep mode operation by changing the state to the sleep mode with reference to the sleep mode operation parameter.

The sleep mode includes a sleep window (SW) in which data reception is not possible, and a listening window (LW) in which data reception is possible.

In the sleep mode, the base station transmits a TRF-IND (Traffic-Indication) message to the terminal to indicate whether there is traffic to be delivered to the terminal during the listening window (S103).

The TRF-IND message indicating whether there is traffic is set to a positive indication when there is traffic, and to a negative indication when there is no traffic.

If the terminal receives the positive TRF-IND message, the terminal transmits and receives the generated data traffic during the listening window (S104), and enters the sleep period (SW) again to perform the sleep mode operation. .

In the present specification, when the terminal operating in the sleep mode does not receive the traffic indication message including the updated sleep identifier in the listening window of the sleep mode, the terminal includes the updated sleep identifier in the traffic indication response message and transmits the following. The purpose is to provide correct interpretation of the traffic indication message transmitted in the sleep period.

The present disclosure provides a method of operating a base station for supporting a sleep mode in a broadband wireless communication system, the method comprising: transmitting a sleep response message including sleep identification information to a terminal in a sleep mode entry process; When the sleep identification information is updated, transmitting a traffic indication message including the updated sleep identification information to the terminal in a listening window of a sleep mode; Receiving a traffic indication request message from the terminal after the listening period; And transmitting a traffic indication response message including the updated sleep identification information to the terminal.

In addition, the sleep identification information is characterized in that the identifier used to distinguish the terminal in the sleep mode state.

In addition, the updated sleep identification information is characterized by consisting of a pair of sleep identifier (OLD SLPID) used by the terminal and a new sleep identifier (NEW SLPID) in place of the sleep identifier used by the terminal.

The new slip identification information may be included in the traffic indication response message when the slip identification information is updated.

The sleep identification information may be updated after entering the sleep mode.

The sleep identification information may be updated when an empty sleep identifier not assigned to the terminal occurs among sleep identifiers allocated to the sleep identifier group.

In addition, the present disclosure provides a method for operating a terminal performing a sleep mode in a broadband wireless communication system, the method comprising: receiving a sleep response message including sleep identification information from a base station in a sleep mode entry process; Transmitting a traffic indication request message to the base station after the listening period when the traffic indication message and the unicast data are not received from the base station during the sleep period of the sleep mode; Receiving a traffic indication response message including new sleep identification information in place of the sleep identification information from the base station; And updating the new sleep identification information based on the received traffic indication response message.

The method may further include checking whether there is traffic to be transmitted to the terminal based on the updated sleep identification information after receiving the traffic indication message in the sleep mode listening section following the listening section. .

The traffic indication message may further include the updated sleep identification information when the sleep identification information is updated.

In addition, the present specification provides a terminal for performing a sleep mode in a broadband wireless communication system, comprising: a central processing unit; A memory unit; And a wireless communication (RF) unit, the wireless communication unit comprising: a transmitting module for transmitting a wireless signal; A receiving module for receiving a wireless signal; And controlling the receiving module to receive a sleep response message including sleep identification information from a base station in a sleep mode entry process, and when the traffic indication message and the unicast data are not received from the base station during the sleep period of the sleep mode, Control the transmitting module to transmit a traffic indication request message to the base station after the listening period, and control the receiving module to receive a traffic indication response message including new sleep identification information in place of sleep identification information from the base station. And a wireless communication controller, wherein the central processing unit extracts the new sleep identification information from the received traffic indication response message and controls to update the sleep identifier previously assigned to the terminal with the extracted new sleep identification information. Ha .

The new slip identification information may be included in the traffic indication response message when the slip identification information is updated.

In addition, the present specification provides a base station for supporting a sleep mode in a broadband wireless communication system, comprising: a central processing unit; A memory unit; And a wireless communication (RF) unit, the wireless communication unit comprising: a transmitting module for transmitting a wireless signal; A receiving module for receiving a wireless signal; And transmitting a sleep response message including sleep identification information to the terminal during a sleep mode entry process, and when the sleep identification information is updated, a traffic indication message including the updated sleep identification information in the sleep mode listening interval ( Controlling the transmission module to transmit to the terminal in a listening window, and after the listening period, if a traffic indication request message is received from the terminal through the receiving module, the traffic indication response message including the updated sleep identification information It characterized in that it comprises a wireless communication controller for controlling the transmission module to transmit to the terminal.

In this specification, the updated sleep identifier is included in the traffic indication response message and transmitted to the terminal, so that the terminal correctly interprets the traffic indication message transmitted in the next sleep period even if the terminal does not receive the traffic indication message during the listening interval. Allows smooth mode operation.

1 is a flowchart sequentially illustrating a typical sleep mode operation.
2 is a flowchart illustrating a method of updating a sleep identifier of a sleep mode terminal according to one embodiment of the present specification;
3 is a flowchart illustrating a method of operating a terminal for updating a sleep identifier when the terminal does not receive a traffic indication message according to an embodiment of the present disclosure.
4A is an internal block diagram of a terminal or a base station according to an embodiment of the present disclosure.
4B illustrates an internal block diagram of the wireless communication unit of FIG. 4A.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the scope of the present invention with reference to the accompanying drawings.

Hereinafter, the term terminal is used, but the terminal may be referred to as a subscriber station (SS), a user equipment (UE), a mobile equipment (ME), or a mobile station (MS). The terminal may be a portable device having a communication function, such as a mobile phone, a PDA, a smart phone, a notebook computer, or a non-portable device such as a PC or a vehicle-mounted device.

The present specification provides a method for updating a sleep identifier of a sleep mode terminal when the sleep mode terminal does not receive a traffic indication message including an updated sleep identifier.

First, before describing a method for updating a sleep identifier of a sleep mode terminal provided herein, parameters and messages used for a sleep mode operation will be described.

Sleep identifier ( SLPID ; SLeep IDentifier )

The sleep identifier (ID) is a value assigned through a sleep response (SLP-RSP: Sleep-Response) message in the process of the terminal transitions from the awake mode to the sleep mode, and is unique only to the terminals in the sleep mode. Used as a value. That is, the sleep identifier is an identifier used to distinguish a terminal in a sleep mode including a listening window.

In addition, when the terminal transitions from the sleep mode to the awake mode, the sleep identifier pre-assigned to the terminal is returned to the base station, and is reused through another sleep response (SLP-RSP) message to another terminal to transition to the sleep mode. Can be. In general, the sleep identifier has a size of 10 bits and may support up to 1024 terminals that perform a sleep mode operation.

traffic  indication( TRF - IND : Traffic Indication ) message

The traffic indication message is a message transmitted by the base station to the terminal during the listening window in the sleep mode, and is a message indicating that there is packet data to be transmitted to the terminal by the base station.

The traffic indication message is a broadcasting message that is transmitted in a broadcasting manner unlike the SLP-REQ message and the SLP-RSP message exchanged between the terminal and the base station when entering the sleep mode. The traffic indication message is a message indicating whether there is packet data to be transmitted from the base station to a predetermined terminal, and the terminal decodes the broadcasted traffic indication message during the listening window (LISTENING WINDOW) to transition to awake mode. Or it is determined whether to return to the sleep mode again.

If the terminal transitions to the awake mode, the terminal checks frame sync and if the frame sequence number expected by the terminal does not match, the packet is lost in the awake mode. Retransmission of lost packet data may be required.

On the contrary, if the terminal does not receive the traffic indication message during the listening window or receives the traffic indication message, but the value indicating the positive indication is not indicated, the terminal enters the sleep mode. You can also go back.

Table 1 below shows the format of an AAI-TRF-IND message.

Field Size (bits) Value / Description Condition AAI-TRF-IND message_format () { FRMT One This indicates type of Traffic Indication in AAI-TRF-IND message.
0: It indicates the SLPID bitmap-based traffic indication
1: It indicates the SLPID-based traffic indication Emergency Alert Indication One Used to indicate the presence of emergency information for supporting the emergency alert service
0b0: there is no emergency information
0b1: there is emergency information if (FMT == 0) { SLPID Group Indication Bitmap 32 It indicates the existence of each SLPID group
N-th bit of SLPID-Group Indication Bitmap [MSB corresponds to N = 0] is allocated to
SLPID Group that includes AMS with SLPID values from N * 32 to N * 32 + 31
0: There is no traffic for any of the 32 AMSs that belong to the SLPID-Group
1: There is traffic for at least one AMS in SLPID-Group. Traffic Indication Bitmap N * 32 It indicates the traffic indication for 32 AMSs in each SLPID group
Each Traffic Indication bitmap comprises multiples of 32-bit long Traffic Indication units. A Traffic Indication unit for 32 SLPIDs is added to AAI-TRF-IND message whenever its SLPID Group is set to 1
32 bits of Traffic Indication Unit (starting from MSB) are allocated to AMS in the ascending order of their SLPID values:
0: Negative indication
1: Positive indication
N = The number of '1' in SLPID Group Indication Bitmap (ie the number of SLPID Group which has positive traffic indication) } else { Num_of_SLPIDs 6 It indicates the number of SLPID included in AAI-TRF-IND message
0 to 63 for (i = 0; i <Num_of_SLPIDs; i ++) { SLPID 10 Each SLPID is used to indicate the positive traffic indication for an AMS
0-1023 } } }

Referring to Table 1, the parameters included in the traffic indication message will be described.

(1) FRMT

The FRMT is a method of indicating whether there is traffic to be delivered to the UE in the sleep mode, and indicates whether to use the sleep identifier bitmap or the sleep identifier.

Here, the sleep identifier bitmap (SLPID bit-map) represents a set of indication indexes allocated by one bit for each sleep identifier allocated to the terminal to distinguish the terminals that have transitioned to the sleep mode.

For example, when the FRMT parameter is set to '0', this indicates a traffic indication based on a sleep identifier bitmap, and when set to '1', it indicates a traffic indication based on a sleep identifier.

(2) SLPID-Group Indication Bitmap

The SLPID-Group Indication Bitmap (SLPID-Group Indication Bitmap) indicates whether traffic is indicated to the UE belonging to each sleep identifier group.

The sleep identifier may have a value from 0 to 1023, and is divided into 32 sleep identifier groups. Therefore, each sleep identifier group may have the following range.

Sleep identifier group # 0 (most significant bit) corresponds to sleep identifiers 0-31. Sleep identifier group # 1 corresponds to sleep identifiers 32 to 63, .... Sleep identifier group # 31 corresponds to sleep identifiers 992 to 1023. The sleep identifier group indication bitmap is a 32-bit field in which each bit is assigned to each sleep identifier group. That is, the most significant bit in this field is assigned to sleep identifier group # 0, and the next bit is assigned to sleep identifier group # 1.

Accordingly, the nth bit bn, (n = 0 to 31) of the sleep identifier group indication bitmap may be interpreted in the following manner. That is, bn = 0 means that there is no traffic for all 32 terminals belonging to the sleep identifier group #n. In this case, terminals in the sleep mode belonging to the sleep identifier group #n may return to the sleep mode again.

In addition, bn = 1 indicates that there is traffic for one or more terminals belonging to the sleep identifier group #n. In this case, the terminal in the sleep mode belonging to the sleep identifier group # n will read its traffic indication bitmap in the traffic indication message.

(3) Traffic Indication Bitmap

The traffic indication bitmap consists of a plurality of 32-bit long traffic indication units for all sleep identifier groups for which the sleep identifier group indication bit is set to '1'.

In the 32-bit traffic indication unit, the bits (starting from the most significant bit) are assigned to the terminal in ascending order of sleep identifiers. Each bit transmits traffic information for the corresponding terminal as follows.

For example, '0' represents a negative indication and '1' represents a positive indication.

(4) Number of sleep identifiers (Num_of_SLPIDs)

Indicates the number of sleep identifiers with positive indications.

(5) Sleep Identifier (SLPID)

Sleep identifier for a terminal having traffic to be transmitted in downlink

(6) Traffic Location Indicator Bitmap

Each bit corresponds to a sleep identifier with a positive traffic indication and indicates whether the corresponding data exists only in the second half of the listening window (after half of the listening window).

In addition, the traffic indication message may further include a sleep identifier update parameter.

(7) update sleep identifier

The sleep identifier update parameter provides a quick way to change the sleep identifier used by the sleep mode terminal.

The sleep identifier update parameter indicates a new sleep identifier in place of the old sleep identifier. The sleep identifier update parameter is configured by a pair of sleep identifier (OLD SLPID) and new sleep identifier (NEW SLPID) values currently used by terminals, and may include a plurality of pairs. This sleep identifier update parameter is applied from the next listening window.

Hereinafter, a brief description will be given of a sleep mode operation when a terminal receives a traffic indication (TRF-IND) message transmitted from a base station.

The base station transmits a traffic indication (TRF-IND) message for indicating whether there is traffic to be transmitted to the terminal in the listening window (LW: Listening Window) of the sleep period to the terminal.

In this case, the traffic indication message flag (TIMF) included in the sleep request and sleep response message (SLP-REQ / RSP message) is set to '1', the base station is a terminal belonging to one terminal or one group If a traffic indication message is sent to the client.

In addition, when the base station updates the sleep identifier assigned to the terminal through a sleep response (SLP-RSP) message, traffic including the sleep identifier (Old SLPID) and the updated new sleep identifier (New SLPID) used by the current terminal Send an instruction message to the terminal.

Here, updating the sleep identifier means that the base station reassigns the sleep identifier allocated to the terminal in the sleep mode to the new sleep identifier during the sleep mode procedure.

The determination of whether the sleep identifier is required to be updated is determined based on whether there is an empty sleep identifier (empty SLP_ID) in a list of sleep identifiers having a smaller number than the current sleep identifier of the terminal among all identifier lists managed by the base station. The empty sleep identifier may correspond to an identifier returned to the base station while a mode transition is made while the terminal is already assigned and used in the awake mode. If there are a plurality of empty identifiers, the smallest of them can be newly assigned and updated.

Through this method, the terminal may be continuously updated with a smaller identifier number without being fixed to the initially assigned sleep identifier.

For example, when the smallest sleep identifier that the base station can assign to the terminal entering the sleep mode is 1 and the sleep identifier assigned to the first terminal is 99, the sleep identifier 99 and the first identifier If there is a sleep identifier that is not in use, the smallest number among them can be newly assigned to the terminal.

If it is determined that the base station needs to update the sleep identifier of the terminal, the base station updates the sleep identifier of the terminal.

In addition, the determination of whether the sleep identifier update is required may be determined by whether an empty sleep identifier exists among sleep identifiers of terminals belonging to each SLPID Group.

That is, when the SLPIDs of the sleep mode terminal are distributed for each sleep identifier group, the base station may perform sleep identifier update to allocate the SLPIDs distributed in the respective SLPID groups to the same sleep identifier group.

The SLPID Group Indication bitmap is composed of 32 bits, and up to 32 sleep mode terminals may be included in each SLPID group.

Therefore, when all 32 bits of the SLPID Group Indication bitmap are set to '1', 1024 sleep mode terminals check the traffic indication bitmap transmitted through the TRF-IND message.

For example, when a plurality of sleep mode terminals transition to the normal mode and only about 100 terminals remain in the sleep mode, the SLPID of each sleep mode terminal (100 terminals) is evenly distributed to 32 bits of the SLPID Group Indication bitmap. Spread may occur.

 That is, when the sleep mode terminal through which the buffered DL traffic is transmitted is spread over all bits of the SLPID Group Indication bitmap 32 bits, the base station sets all of the 32 bits of the SLPID Group Indication bitmap to '1'.

In this case, the size of the traffic indication bitmap generates an overhead of the number of bits * 32 bits in which the SLPID Group indication bitmap is set to 1.

Therefore, in this case, the base station updates the SLPID of the sleep mode terminal so that as many sleep mode terminals as possible belong to the same sleep group.

That is, the base station updates the SLPID assigned to the terminal, thereby preventing the 32-bit SLPID Group Indication bitmap from being set to '1' simultaneously, thereby reducing the overhead of the traffic indication bitmap.

The base station configures and stores the sleep identifier currently used by the terminal in the SLP_ID_Update field of the TRF-IND message and the sleep identifier information newly allocated to the terminal. Preferably, a pair of sleep identifiers currently used by the terminal and sleep identifier information to be newly allocated to the terminal is configured.

The SLP_ID_Update parameter consists of a sleep identifier (OLD SLPID) currently assigned to a terminal and an Old_New_SLP_ID storing a sleep identifier (NEW SLPID) newly assigned to the terminal as a pair.

In addition, since the SLP_ID_Update is a TLV Encoding type parameter, it is included in a TRF-IND message and transmitted to the terminal only when necessary.

Next, when the terminal receives the traffic indication message from the base station, the terminal checks whether there is a positive traffic indication (eg, a SLPID Group Indication Bitmap and a Traffic Indication Bitmap or the UE). Via the SLPID assigned to the server.

When the at least one sleep identifier is set to a positive traffic indication and the traffic location indicator is set to '1', the base station transmits the traffic location indicator bitmap to the terminal by including the traffic location indicator bitmap in the traffic indication message.

In this case, the traffic location indicator field indicates whether the terminal indicated by the positive traffic should maintain the sleep mode in the first half of the listening window (that is, the section corresponding to the front N / 2 when the length of the listening window is N).

That is, the first half of the listening window is defined as first frames (N / 2 sections) of the listening window having a listening window length N.

If the terminal receives a positive traffic indication from the base station during the listening window of the sleep period, the current sleep period (eg, including the listening window) is the New Sleep Cycle Flag (NSCF) (single day) to synchronize the listening window of the sleep mode terminals. For example, it will be reset to a value corresponding to an initial sleep period, a new initial sleep period, or twice the previous sleep period.

That is, when the terminal receives a positive traffic indication from the base station during the listening window, the terminal continuously maintains the awake mode and consequently transitions to the awake mode.

When the base station transmits a positive traffic indication to a specific terminal, the base station transmits at least one downlink MAC PDU to the terminal during the listening window.

However, when the terminal receives a negative traffic indication from the base station, and the terminal does not have uplink signaling with the base station or traffic to be transmitted to the base station, the terminal terminates the listening window and sleep window during the remaining period of the sleep period. Proceed to the operation. That is, the terminal transitions back to the sleep mode.

When the base station transmits a negative traffic indication to the terminal, the base station does not transmit any downlink data traffic to the terminal for the remaining period of the listening window.

In addition, when the terminal receives a positive traffic indication from the base station, and the listening window is not explicitly terminated by the sleep control header (SCH), the terminal to the remaining section of the listening window for receiving unicast data from the base station waiting.

Hereinafter, when the traffic indication message including the updated sleep identifier provided herein is lost or not detected by the terminal, a method of updating the sleep identifier of the terminal will be described.

2 is a flowchart illustrating a method of updating a sleep identifier of a sleep mode terminal according to one embodiment of the present specification.

First, if the base station updates the sleep identifier assigned to the sleep mode terminal during the sleep mode entry process (S201), the base station transmits a traffic indication message including the updated sleep identifier to the terminal (S202).

In this case, when the base station updates the sleep identifier, as described above, when there is an empty sleep identifier (empty SLP_ID) in the sleep identifier list having a smaller number than the current sleep identifier of the terminal among all identifier lists managed by the base station. Occurs.

The empty sleep identifier may correspond to an identifier returned to the base station while a mode transition is made while the terminal is already assigned and used in the awake mode. If there are a plurality of empty identifiers, the smallest of them can be newly assigned and updated.

In addition, when the SLPIDs of the sleep mode terminal are distributed for each sleep identifier group, the base station may perform sleep identifier update to allocate the SLPIDs distributed in the respective SLPID groups to the same sleep identifier group.

When the traffic indication message flag (TIMF) is set to '1', the traffic indication message is transmitted to the terminal in the first frame during the listening window of the sleep mode.

If the traffic indication message is lost or not detected, the terminal remains awake for the rest of the listening window.

However, if the terminal does not receive any unicast data as well as the traffic indication message from the base station during the listening window, the terminal transmits a traffic indication request message to the base station (S203).

That is, the terminal transmits a traffic indication request (TRF-IND-REQ) message to the base station after the currently set listening window to request the base station for the location of the next scheduled listening window.

However, although the traffic indication message transmitted by the base station is lost in the transmission process or not detected by the terminal, when the terminal receives unicast data from the base station during the listening window, the terminal determines that the traffic indication is positive.

That is, when the terminal receives unicast data from the base station during the listening window, the terminal does not transmit the traffic indication request message to the base station because the traffic indication transmitted from the base station is regarded as positive.

Hereinafter, it is assumed that the terminal does not receive a traffic indication message and any unicast data from the base station during the listening period.

When the base station receives the traffic indication request message from the terminal, the base station transmits a traffic indication response (TRF-IND-RSP) message including the size of the next sleep period and the start frame number to the terminal in unicast. That is, the base station responds to the traffic indication request message by transmitting the traffic indication response message to the terminal.

In this case, the traffic indication response message further includes an updated SLPID transmitted through the traffic indication message.

That is, the base station transmits a traffic indication message including the updated sleep identifier to the terminal after the sleep identifier is updated, and then receives the traffic indication request message after the listening window of the sleep period from the terminal, the updated sleep The identifier is included in the traffic indication response message and transmitted to the terminal.

In addition, when the sleep identifier is updated again after transmitting the traffic indication message, the base station may transmit a traffic indication response message including the updated sleep identifier after the transmission of the traffic indication message to the terminal.

The terminal updates the sleep identifier (OLD SLPID) currently used by the terminal to a new sleep identifier (NEW SLPID) by receiving the traffic indication response message from the base station (S205).

If the terminal does not receive the traffic indication response message from the base station until the T43 timer expires, the terminal retransmits the traffic indication request message to the base station. This process is repeated until the terminal successfully receives the traffic indication response message from the base station.

Thereafter, the terminal performs the sleep mode by synchronizing with the next sleep period. That is, the terminal receives the traffic indication message from the base station in the listening window of the next sleep period (S206).

Table 2 below shows an example of an AAI-TRF-IND-REQ message format.

Field Size (bits) Value / Description Condition AAI-TRF-IND-REQ message_format () { Control Message Type 8 This indicates type of control message is AAI-TRF-IND-REQ message

Table 3 below shows an example of an AAI-TRF-IND-RSP message format.

Field Size (bits) Value / Description Condition AAI-TRF_IND-RSP message_format () { Frame_Number 10 The least significant 10 bits of the frame number in which incoming LW will start
0-1023 Sleep Cycle Length 10 The length of Sleep Cycle which contains the next scheduled Listening Window. If the AMS receives the traffic indication during the next scheduled Listening Window, the (current) Sleep Cycle shall be set to this value at that time.
Value: 0 ~ 1023
Sleep Cycle Length = Value + 1 SLPID 10 Updated SLPID .
New SLPID to replace the AMS's old  SLPID with .
When the ABS has sent the AAI - TRF - IND  message including SLPID update of the  AMS and it receives AAI - TRF - IND - REQ  from the AMS , the ABS shall include  this parameter in AAI - TRF - IND - RSP . Shall be  included when  the SLPID is updated . }

With reference to Table 3, the parameters included in the TRF-IND-RSP message will be described.

(1) Frame number (Frame_Number)

The frame number indicates the lower 10 bits of the frame number at which the next scheduled listening window will begin.

(2) Sleep Cycle Length

The sleep period length parameter indicates the length of the sleep period in which the next scheduled listening window is included when the sleep period is doubled due to negative traffic indication during the next scheduled listening window.

(3) Sleep Identifier (SLPID)

Indicates an updated sleep identifier. That is, it indicates a new sleep identifier (NEW SLPID) to replace the sleep identifier (OLD SLPID) currently being used by the terminal.

The updated sleep identifier is included in the traffic indication response message transmitted to the terminal when the base station receives the traffic indication request message from the terminal after transmitting the traffic indication message including the updated sleep identifier.

3 is a flowchart illustrating a method of operating a terminal for updating a sleep identifier when the terminal does not receive a traffic indication message according to an embodiment of the present disclosure.

Hereinafter, it is assumed that the base station updates the sleep identifier assigned to the terminal during the sleep mode entry process and then transmits the new sleep identifier (NEW SLPID) to the terminal by including the new sleep identifier (NEW SLPID) in the traffic indication message.

First, when the terminal does not receive a traffic indication message from the base station in the listening window (listening interval) of the sleep mode (S301), the terminal maintains an awake state during the listening period. Here, the case where the terminal does not receive the traffic indication message may be a case where the traffic indication message is lost in the transmission process or not detected by the terminal due to other reasons.

Thereafter, when the terminal does not receive any unicast data from the base station during the listening period (S302), the terminal transmits a traffic indication request message to the base station after the listening period (S303). If no traffic indication message and any unicast data are received from the base station during the listening period, the traffic indication request message is transmitted to the base station after the listening period.

Next, the terminal receives a traffic indication response message including the updated sleep identification information from the base station (S304). The updated sleep identification information includes a sleep identifier (OLD SLPID) and a new sleep identifier (NEW) currently used by the terminal. SLPID) may be configured as a pair.

After extracting the updated sleep identifier (NEW SLPID) from the received traffic indication response message, the terminal updates the sleep identifier (OLD SLPID) currently used by the updated sleep identifier (NEW SLPID). S305)

Thereafter, the terminal receives the traffic indication message from the base station in the listening window of the next sleep period, and checks whether there is traffic transmitted from the base station. That is, the terminal performs the sleep mode through the traffic indication response message including the updated sleep identifier.

4A illustrates an internal block diagram of a terminal or a base station according to an embodiment of the present specification.

First, a case in which the internal block diagram of FIG. 4A corresponds to a terminal will be described.

The terminal 400 may include a central processing unit 420, a memory unit 430, and a wireless communication (RF) unit 410.

The central processing unit 420 generally controls the overall operation of the terminal. In particular, new sleep identification information is extracted from the traffic indication response message received in the wireless communication unit, and the sleep identifier previously assigned to the terminal is controlled to be updated with the extracted new sleep identification information.

Here, the sleep identification information refers to an identifier used to distinguish a terminal in a sleep mode state. That is, the sleep identification information indicates the SLPID.

The memory unit 430 may store a program for the operation of the controller, and may temporarily store input / output data.

The radio communication (RF) unit 410 transmits and receives radio signals to and from the outside, and includes a transmitting module 411 for transmitting a radio signal, a receiving module 412 for receiving a radio signal, and a radio communication controller 413. It is configured by.

The wireless communication controller 413 controls the receiving module to receive a sleep response message including sleep identification information from a base station in a sleep mode entry process.

In addition, when the wireless communication controller 413 does not receive the traffic indication message and the unicast data from the base station during the listening period in the sleep mode, the transmission module to transmit the traffic indication request message to the base station after the listening period. To control. In addition, the wireless controller 413 controls the receiving module to receive a traffic indication response message including new sleep identification information in place of sleep identification information from the base station.

Next, a case in which the internal block diagram of FIG. 4A corresponds to a base station will be described.

The base station 400 may include a central processing unit 420, a memory unit 430, and a wireless communication (RF) unit 410.

The central processing unit 420 generally controls the overall operation of the terminal.

The memory unit 430 may store a program for the operation of the controller, and may temporarily store input / output data.

The radio communication (RF) unit 410 transmits and receives radio signals to and from the outside, and includes a transmitting module 411 for transmitting a radio signal, a receiving module 412 for receiving a radio signal, and a radio communication controller 413. It is configured by.

The wireless communication controller 413 controls the transmitting module to transmit a sleep response message including sleep identification information to the terminal during a sleep mode entry process. In addition, when the sleep identification information is updated, the wireless communication controller 413 transmits a traffic indication message including the updated sleep identification information to the terminal in a listening window in a sleep mode. To control.

In addition, when the traffic indication request message is received from the terminal through the receiving module after the listening period, the wireless communication controller 413 transmits a traffic indication response message including the updated sleep identification information to the terminal. Control the transmission module.

Here, the sleep identification information refers to an identifier used to distinguish a terminal in a sleep mode state. That is, the sleep identification information indicates the SLPID.

4B is a diagram illustrating an internal block diagram of the wireless communication unit of FIG. 4A.

As shown in FIG. 4B, the transmission module 411 includes an encoding and modulator 411-1, a subcarrier mapper 411-2, an OFDM modulator 411-3, and an RF transmitter 411-4. Can be configured.

In addition, the receiving module 412 may include an RF receiver 412-1, an OFDM demodulator 412-2, a subcarrier demapper 412-3, a demodulator, and a decoder 412-4. have.

First, the RF receiver 412-1 downconverts an RF band signal received through an antenna to a baseband signal. The OFDM demodulator 412-2 divides the signal provided from the RF receiver 412-1 in OFDM symbol units, removes a CP, and restores signals for each subcarrier through an FFT operation. The subcarrier demapper 412-3 extracts signals to be demodulated and decoded from the signals for each subcarrier provided from the OFDM demodulator 412-2. The demodulator and decoder 412-4 demodulates and decodes the signals provided from the subcarrier demapper 412-3 into a bit string.

The encoder and modulator 411-1 encodes and modulates a bit string provided from the data buffer and converts the bit string into complex symbols. The subcarrier mapper 411-2 maps the complex symbols provided from the encoder and modulator 411 to the subcarriers.

The OFDM modulator 411-3 converts subcarrier signals provided from the subcarrier mapper 411-2 into a time domain signal through an IFFT operation, and configures an OFDM symbol by inserting a CP. The RF transmitter 411-4 up-converts the baseband signal provided from the OFDM modulator 411-3 into an RF band signal and transmits it through an antenna.

The wireless communication controller controlling the transmitting module and the receiving module interprets the control message of the MAC layer received from the base station and provides the same to the central processing unit 420.

Although not shown in FIG. 4B, the data buffer stores data received from the base station and data to be transmitted to the base station, and stores the stored data to the encoder and modulator 411-1 under the control of the central processing unit 420. Output

400: terminal, base station
410: wireless communication unit
420: central processing unit
430: memory unit

Claims (17)

A method of operating a base station for supporting a sleep mode in a broadband wireless communication system,
Transmitting a sleep response message including sleep identification information to the terminal in a sleep mode entry process;
When the sleep identification information is updated, transmitting a traffic indication message including the updated sleep identification information to a terminal in a listening window;
Receiving a traffic indication request message from the terminal after the listening period when the terminal does not receive the traffic indication message and the unicast data including the updated sleep identification information during the listening period; And
And transmitting a traffic indication response message including the updated sleep identification information to the terminal. The method of claim 1,
The sleep identification information is characterized in that the identifier used to distinguish the terminal in the sleep mode. The method of claim 1,
The updated sleep identification information comprises a pair of a sleep identifier (OLD SLPID) used by the terminal and a new sleep identifier (NEW SLPID) in place of the sleep identifier used by the terminal. The method of claim 3, wherein
The new sleep identification information is included in the traffic indication response message when the sleep identification information is updated, characterized in that transmitted. The method of claim 1,
The sleep identification information is updated after entering a sleep mode. The method of claim 1,
The sleep identification information is updated when an empty sleep identifier not assigned to the terminal among the sleep identifiers assigned to the sleep identifier group is generated. delete A method of operating a terminal performing a sleep mode in a broadband wireless communication system,
Receiving a sleep response message including sleep identification information from a base station in a sleep mode entry process;
Transmitting a traffic indication request message to the base station after the listening period when a traffic indication message including updated sleep identification information and unicast data is not received from the base station during a listening window;
Receiving a traffic indication response message including new sleep identification information in place of the sleep identification information from the base station; And
Based on the received traffic indication response message, updating with the new sleep identification information. The method of claim 8,
And receiving a traffic indication message in a sleep mode listening period following the listening period, and then checking whether there is traffic to be transmitted to the terminal based on the updated sleep identification information. delete The method of claim 8,
The sleep identification information is characterized in that the identifier used to distinguish the terminal in the sleep mode. The method of claim 8,
The updated sleep identification information comprises a pair of a sleep identifier (OLD SLPID) used by the terminal and a new sleep identifier (NEW SLPID) in place of the sleep identifier used by the terminal. The method of claim 8,
The new sleep identification information is included in the traffic indication response message when the sleep identification information is updated, characterized in that transmitted. A terminal for performing a sleep mode in a broadband wireless communication system,
A central processing unit;
Memory unit; And
A radio communication (RF) unit,
The wireless communication unit,
A transmission module for transmitting a wireless signal;
A receiving module for receiving a wireless signal; And
In the sleep mode entry process, the receiving module controls the receiving module to receive a sleep response message including the sleep identification information from the base station, and the traffic indication message and the unidirectional information including the sleep identification information updated from the base station during a listening window. If no cast data is received, the control module transmits a traffic indication request message to the base station after the listening period, and the traffic indication response message includes new sleep identification information in place of sleep identification information from the base station. It includes a wireless communication controller for controlling the receiving module to receive,
And the central processing unit extracts the new sleep identification information from the received traffic indication response message and controls to update the sleep identifier previously assigned to the terminal with the extracted new sleep identification information. The method of claim 14,
The sleep identification information is a terminal, characterized in that the identifier used to distinguish the terminal in the sleep mode state. The method of claim 14,
The new sleep identification information is included in the traffic indication response message when the sleep identification information is updated. A base station for supporting a sleep mode in a broadband wireless communication system,
A central processing unit;
Memory unit; And
A radio communication (RF) unit,
The wireless communication unit,
A transmission module for transmitting a wireless signal;
A receiving module for receiving a wireless signal; And
In the sleep mode entry process, a sleep response message including the sleep identification information is transmitted to the terminal, and when the sleep identification information is updated, a traffic indication message including the updated sleep identification information is transmitted to a listening window. Control the transmitting module to transmit to the terminal,
If the terminal does not receive the traffic indication message and the unicast data including the updated sleep identification information during the listening period, if the traffic indication request message is received from the terminal after the listening period, through the receiving module, And a wireless communication controller controlling the transmitting module to transmit a traffic indication response message including the updated sleep identification information to the terminal.

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