KR20070015994A - Method for updating idle mode location in a wideband wireless access communication system - Google Patents

Abstract

The present invention provides a method for determining a location update performance of a mobile station having the idle mode in a broadband wireless access communication system in which there is a mobile station capable of transitioning to an idle mode to minimize power consumption. If it is detected that the first counter value previously stored and the second counter value received in the current frame interval, and if the first counter value and the second counter value is the same, the previously stored base station And comparing the identifier with the current base station identifier received in the current frame period, and if the previous base station identifier and the current base station identifier are different from each other, not receiving information necessary for performing a location update.

Idle Mode, Paging, Position Update, DCD, UCD

Description

How to update the idle mode location in a broadband wireless access communication system {METHOD FOR UPDATING IDLE MODE LOCATION IN A WIDEBAND WIRELESS ACCESS COMMUNICATION SYSTEM}

1 is a diagram schematically illustrating a paging service structure of a general IEEE 802.16e communication system.

2 is a flowchart illustrating a process of performing location update by a mobile station in a conventional broadband wireless access communication system.

FIG. 3 is a diagram illustrating a method of processing a Broadcast Control Pointer IE message when a mobile station to perform a location update moves by changing a base station in a broadband wireless access communication system according to an embodiment of the present invention.

4A and 4B are flowcharts illustrating a process of a mobile station performing a location update in a broadband wireless access communication system according to an embodiment of the present invention.

The present invention relates to a broadband wireless access communication system, and more particularly to a method for location update of a mobile station having an idle mode.

In the 4th Generation (hereinafter, referred to as '4G') communication system, users of services having various quality of service (hereinafter referred to as 'QoS') having a transmission rate of about 100 Mbps are used. Active research is underway to provide them. In particular, in 4G communication systems, broadband wireless such as a wireless local area network (hereinafter, referred to as a 'LAN') system and a wireless metropolitan area network (hereinafter, referred to as a 'MAN') system are used. Research is being actively conducted to support high-speed services in a form of guaranteeing mobility and quality of service (BoS) in a broadband wireless access (BWA) communication system. (Institute of Electrical and Electronics Engineers) 802.16 communication system.

The IEEE 802.16 communication system is referred to as Orthogonal Frequency Division Multiplexing (OFDM) to support a broadband transmission network on a physical channel of the wireless MAN system. / Orthogonal Frequency Division Multiple Access (OFDMA) is a communication system to which the scheme is applied.

Meanwhile, according to the IEEE 802.16e communication system standard, a mobile station can operate in idle mode to minimize power consumption when there is no traffic to transmit and receive for a predetermined time. Therefore, if there is no traffic to transmit and receive, the mobile station deactivates a de-registration request (hereinafter referred to as 'DREG-REQ') message to a serving base station currently performing communication in order to operate in an idle mode. Send. The serving base station receiving the DREG-REQ may approve an idle mode operation by transmitting a DREG command (hereinafter, referred to as a 'DREG-CMD') message to the mobile station. Tables 1 and 2 show the DREG-REQ and DREG-CMD message formats.

As shown in Table 1, the Management Message Type field is referred to as a Medium Access Control (MAC) defined in IEEE 802.16. A field for distinguishing management messages. The deregistration request code (De-registration_Request_Code) is a field for indicating the purpose of the mobile station transmitting the DREG-REQ message. Type / Length / Value encoded parameters field includes a number of TLV encoded fields.

As shown in Table 2, the Management Message Type field is a field for distinguishing MAC management messages defined in IEEE 802.16. The Action Code (hereinafter referred to as 'Action Code') field is a field indicating the purpose of the DREG-CMD message. The TLV encoded parameters field includes a plurality of TLV encoded fields. One of the plurality of TLV encoded fields is a paging information field. The paging information field may be referred to as a paging group ID (hereinafter, referred to as a 'PG-ID'), a paging cycle (PAGING_CYCLE, hereinafter referred to as a 'PAGING_CYCLE') and a paging offset (PAGING_OFFSET) associated with an idle mode operation. It will be referred to as 'PAGING_OFFSET' hereinafter). The PG-ID is a parameter assigned by the system according to the position of the mobile station. That is, the current position information of the mobile station is shown.

The PAGING_CYCLE parameter is a call cycle determined by the system with reference to a paging cycle request requested by the mobile station. The PAGING_OFFSET parameter is a parameter used by the system to determine when to call a specific mobile station by using the frame number of the base station and the PAGING_CYCLE parameter.

Receiving the DREG-CMD message, the mobile station regards a paging segment for 2 to 5 frames from a frame satisfying frame number% paging cycle = paging offset in a channel maintaining synchronization with a serving base station, and paging during the paging segment. A broadcast (MOB_PAG-ADV: MOBile_Paging-Advertisement, hereinafter referred to as 'MOB_PAG-ADV') message is received. Table 3 shows the MOB_PAG-ADV message format.

1 is a diagram schematically illustrating a paging service structure of a general IEEE 802.16e communication system.

Referring to FIG. 1, first, each adjacent cell may be configured as one logical paging group according to its local location. As one embodiment of the paging group, there are four paging groups: PG-ID # 1 (130a), PG-ID # 2 (130b), PG-ID # 3 (130c), and PG-ID # 4 (130d). The paging group includes a plurality of cells. The mobile station 150 may operate in an idle mode, and receiving the service provided from the base station ([150] 140a), through the base station ([150] 140a) and DREG-REQ and DREG-CMD message exchange. All base stations belonging to the PG-ID # 1 130a may call the mobile station 150 using the MOB_PAG-ADV message. Meanwhile, the mobile station 150 may move to a cell managed by the base station 140b belonging to the area of PG-ID # 2 130b. In this case, if the PG_ID of the previously received MOB_PAG-ADV message and the PG_ID of the currently received MOB_PAG-ADV message are different from each other, the mobile station 150 should perform a location update.

The mobile station must first perform ranging in order to perform a location update. However, in order for the mobile station to perform ranging, it will first be called a Downlink Channel Descript (hereinafter referred to as 'DCD') and an Uplink Channel Descript (hereinafter referred to as 'UCD'). Must receive the message. Since the DCD and UCD messages are transmitted from the base station at intervals of up to 10 seconds, the mobile station may not complete the location update during the paging segment.

In the current IEEE 802.16e standard, a mobile station in idle mode can receive the DCD and UCD messages using a Broadcast Control Pointer Information Element (hereinafter, referred to as a 'Broadcast Control Pointer IE') message. It's trying to wake up after N frames.

Next, a process of performing location update by the mobile station in the conventional broadband wireless access communication system will be described with reference to FIG. 2.

2 is a flowchart illustrating a process of performing location update by a mobile station in a conventional broadband wireless access communication system.

Referring to FIG. 2, in step 202, the mobile station proceeds to step 204 in an idle mode. In step 204, the mobile station receives a MOB-PAG-ADV message and proceeds to step 206. In step 206, the mobile station reads an operation code value of the MOB-PAG-ADV message. As a result, the process proceeds to step 208 for 0b00, step 210 for 0b01, and step 212 for 0b10.

In step 208, the mobile station performs no operation.

In step 212, the mobile station performs a network reentry procedure.

In step 210, the mobile station receives a Broadcast Control Pointer IE message and proceeds to step 214. In step 214, the mobile station determines whether there is a DCD_UCD configuration change counter currently stored. As a result of the determination, the flow proceeds to step 216 if there is one, and to step 220 if it does not exist.

In step 216, the mobile station compares a previously stored DCD_UCD configuration change counter value with a currently recognized DCD_UCD configuration change counter value. As a result of the comparison, in step 218, the mobile station can perform location update without having to receive DCD and UCD messages. If not, the mobile station wakes up in the frame period in which the DCD and UCD messages are transmitted in step 220 and proceeds to step 222. In step 222, the mobile station newly receives the DCD and UCD messages and performs a location update.

As described above, the mobile station can know in which frame period the DCD and UCD messages are transmitted from the serving base station according to the DCD_UCD transmission frame information. However, if the mobile station moves to the idle mode and acquires coarse synchronization with another base station, that is, the target base station, DCD and UCD messages cannot be received during the corresponding frame period. Thus, the mobile station must perform decoding on every frame after the corresponding frame in order to receive the DCD and UCD messages. As a result, the mobile station cannot operate in the idle mode, which causes a problem of consuming a lot of power.

In addition, the DCD_UCD configuration change counter value received by the mobile station moving from the serving base station to the target base station in step 216 may be the same as the DCD_UCD configuration change counter value of the serving base station. In this case, since the mobile station performs the location update according to the wrong location update information, a communication disconnection situation may occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an idle mode location update method for minimizing power consumption of a mobile station in a broadband wireless access communication system.

The method of the present invention for achieving the above object; In a broadband wireless access communication system in which a mobile station capable of transitioning to an idle mode for minimizing power consumption exists, the method for determining a location update performance of a mobile station having the idle mode should be performed by the mobile station. If it is detected, comparing the previously stored first counter value with the second counter value received in the current frame section; and if the first counter value and the second counter value are the same, Comparing the current base station identifier received in the current frame period, and if the previous base station identifier and the current base station identifier is different, it comprises the step of not receiving the information necessary to perform the location update.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, only parts necessary for understanding the operation of the present invention will be described, and other background art will be omitted so as not to distract from the gist of the present invention.

The present invention proposes a method capable of minimizing power consumption of a mobile station by allowing a mobile station in an idle mode to efficiently perform a location update in a broadband wireless access communication system.

Prior to the description of the present invention, a method of processing a broadcast control pointer information element (hereinafter, referred to as a 'broadcast control pointer IE') message by a mobile station will be described with reference to Table 4 below. . Table 4 shows the Broadcast Control Pointer IE format.

In order for the mobile station to perform a location update at the current serving base station, DCD_UCD (Downlink Channel Descript, hereinafter referred to as 'DCD') in the Broadcast Control Pointer IE message_Uplink Channel Descript, After the predetermined frame period has passed according to the transmission frame (DCD_UCD Transmission Frame, hereinafter referred to as 'DCD_UCD Transmission Frame') information, after receiving a DCD and UCD message, and performs ranging Location update will be performed.

However, the mobile station moves from the current serving base station to another base station, that is, the target base station before receiving the DCD and UCD messages, and in the frame period designated by the DCD_UCD Transmission Frame even after acquiring coarse synchronization with the target base station. Attempt to receive the DCD and UCD messages. However, as described above, since the mobile station has moved to a target base station, the mobile station cannot receive DCD and UCD from the previous serving base station in the designated frame period. Because of this, the mobile station must decode all the frames it receives until it receives the DCD and UCD messages, which cannot transition to the idle mode where the mobile station minimizes power consumption. Means.

Accordingly, in the present invention, a mobile station that recognizes that the DCD and UCD messages can be received after a predetermined number of frame intervals moves from the current serving base station to a target base station different from the serving base station, and from the target base station downlink map Receive a (DL-MAP) message. The DL-MAP includes BS-ID information, and the mobile station compares the currently received DL-MAP base station identifier with the previously received DL-MAP base station identifier. As a result of the comparison, if the base station identifiers are different, the mobile station ignores the Broadcast Control Pointer IE message. If the base station identifiers are the same, the mobile station decodes the Broadcast Control Pointer IE message to determine whether the DCD_UCD Configuration Change Counter field value is the same as the previously received DCD_UCD Configuration Change Counter field value. If it is the same, the mobile station knows that the DCD or UCD message has not changed and must receive a new DCD and UCD message if it is different. Frame information for newly receiving the DCD and UCD messages can be known by decoding the DCD_UCD Transmission Frame field.

FIG. 3 is a diagram illustrating a method of processing a Broadcast Control Pointer IE message when a mobile station to perform a location update moves by changing a base station in a broadband wireless access communication system according to an embodiment of the present invention.

Referring to FIG. 3, first, the mobile station transmits a de-registration request (hereinafter referred to as 'DREG-REQ') message to the current serving base station to transition to the idle mode (302). The serving base station receiving the DREG-REQ transmits a deregistration command (hereinafter referred to as 'DREG-CMD') to the mobile station (304).

The mobile station receiving the DREG-CMD message operates in correspondence with the action code value of the DREG-CMD message. Here, it is assumed that the operation code value is a value that allows the mobile station to transition to the idle mode. Accordingly, the mobile station transitions to an idle mode and scans neighbor BSs, reselects a serving base station, or lanes in a previously known paging unavailable interval 306. The operation to perform the gong may be performed.

After the paging free period ends, the mobile station receives a DL-MAP message including the base station identifier #N at paging listening interval 308 (310), and again instructs MOB-PAG- to indicate the location update. Receive an ADV message (312). In order to update the location, ranging must be performed, and the ranging can be performed only after receiving a DCD and UCD message. Accordingly, the mobile station decodes the DCD_UCD Transmission Frame field of the Broadcast Control Pointer IE message to recognize that the DCD and UCD messages can be received in a frame capable of receiving the DCD and UCD messages specified in the field from the base station.

Thereafter, the mobile station receives a DL-MAP message in a frame period in which the DCD and UCD messages can be received (314). Here, the base station identifier field of the DL-MAP message is specified as # N + 1. This means that the mobile station moves from a base station having a #N base station identifier to a base station having a # N + 1 base station identifier and obtains an approximate synchronization with the base station having the # N + 1 identifier. Accordingly, in the present invention, the mobile station compares the previous base station identifier with the currently received base station identifier, recognizes the difference, and does not decode the Broadcast Control IE message.

Therefore, for location update of the mobile station, the #N base station broadcasts a MOB-PAG-ADV message instructing to perform location update by a paging retry count. When the MOB-PAG-ADV message includes its identifier information (MS MAC address hash field in Table 3), the mobile station performs network entry corresponding to the accompanying operation code value or lane. Perform the gong process. The ranging request (RNG-REQ) message required for performing the ranging includes an encoding field indicating a location update indication of the mobile station. In addition, the ranging response (RNG-RSP) message includes a location update response encoding field indicating whether the mobile station has successfully updated the location.

However, when the #N base station has no response from the mobile station to expire the paging retry count value, it is necessary to update the location update information of all mobile stations operating in the idle mode through a backbone message. Notify them. Therefore, the base stations attempt to update the location update information by instructing all mobile stations in the idle mode to update the location.

4A and 4B are flowcharts illustrating a process of a mobile station performing a location update in a broadband wireless access communication system according to an embodiment of the present invention.

4A and 4B, first, in step 402, the mobile station proceeds to step 404 in an idle mode. In step 404, the mobile station receives a MOB-PAG-ADV message and proceeds to step 406. In step 406, the mobile station reads an operation code value of the MOB-PAG-ADV message. As a result, the process proceeds to step 408 for 0b00, step 410 for 0b01, and step 412 for 0b10.

In step 408, the mobile station performs no operation.

In step 412, the mobile station performs a network reentry procedure.

In step 410, the mobile station receives a Broadcast Control Pointer IE message and proceeds to step 414. In step 414, the mobile station determines whether there is a DCD_UCD configuration change counter currently stored. As a result of the determination, the flow proceeds to step 416, and if there is no presence, the flow proceeds to step 422.

In step 416, the mobile station compares a previous DCD_UCD configuration change counter value with a current DCD_UCD configuration change counter value. As a result of the comparison, the process proceeds to step 418 and, if it is not the same, to step 422.

In step 418, the mobile station compares a previous base station identifier (BS-ID) with a current base station identifier. As a result of the comparison, in step 420, the mobile station ignores the DCD_UCD Transmission Frame using the recognized downlink information and immediately performs a location update. If it is not the same, the mobile station proceeds to step 422 and determines whether there is at least one paging listening section until the mobile frame reaches the transmission frame section that should receive the DCD and UCD messages. As a result, if there is at least one paging listening section, the mobile station proceeds to step 402 and newly receives a MOB-PAG-ADV message in the paging listening section. However, if there is no paging listening section, the mobile station proceeds to step 424 and the mobile station transitions from the idle mode to the awake mode in the DCD_UCD transmission frame and proceeds to step 426.

In step 426, the mobile station compares a previous base station identifier with a current base station identifier. As a result of the comparison, in step 428, the mobile station receives a DCD and UCD message in the DCD_UCD transmission frame and performs a location update. If it is not the same, the mobile station proceeds to step 430 and the mobile station ignores the DCD_UCD transmission frame and does not perform the location update.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As described above, the present invention has an advantage of preventing abnormal location update performance by efficiently determining whether to perform location update when an idle mode mobile station moves by changing a base station in a broadband wireless access communication system. As a result, unnecessary power consumption of the mobile station can be minimized.

Claims (8)

In a broadband wireless access communication system in which a mobile station capable of transitioning to an idle mode for minimizing power consumption, there is provided a method of determining a location update performance of a mobile station having the idle mode. If the mobile station detects that the location update should be performed, comparing the previously stored first counter value with the second counter value received in the current frame period; If the first counter value and the second counter value are the same, comparing the previously stored base station identifier with the current base station identifier received in the current frame period; And if the previous base station identifier and the current base station identifier are different from each other, not receiving information necessary for performing a location update. The method of claim 1, And the mobile station recognizes the location update by receiving a paging broadcast message instructing the location update from any base station. The method of claim 1, Wherein the first and second counter values are DCD_UCD configuration change counter values. The method of claim 1, The previous BS identifier is present in the DL-MAP message received in the previous downlink frame period. The method of claim 1, Wherein the current base station identifier is present in a DL-MAP message received in a current downlink frame period. The method of claim 1, The mobile station recognizes the location update information by receiving a DCD and a UCD message. The method of claim 6, If there is at least one paging listening section, which is a section for receiving a paging broadcast message during the frame section for receiving the DCD and UCD messages, further comprising receiving a new paging broadcast message in the paging listening section. Said method. The method of claim 1, And if the previous base station identifier and the current base station identifier are the same, performing a location update by using the currently recognized location update information.

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