KR200383529Y1 - Wireless transmit receive unit and access point for managing the association and disassociation of wireless transmit/receive unit - Google Patents

Abstract

A system for managing association and disassociation of a wireless transmit / receive device (WTRU) to an access point (AP) in a wireless communication system. If the AP detects an inactivity state of the WTRU for a predetermined time, the AP sends an association confirmation request message to the WTRU. When the AP receives an acknowledgment (ACK) for its Association Confirm Request message, the AP maintains an association with the WTRU. If the AP does not receive the ACK, the AP disassociates the WTRU.

Description

WIRELESS TRANSMIT RECEIVE UNIT AND ACCESS POINT FOR MANAGING THE ASSOCIATION AND DISASSOCIATION OF WIRELESS TRANSMIT / RECEIVE UNIT}

The present invention relates to a wireless communication system, and more particularly, to a method and system for managing association and disassociation between a wireless transmit / receive device (WTRU) and an access point (AP) in a wireless communication system. It is about.

The wireless communication system includes a plurality of APs and WTRUs. Typically each AP has a specific coverage area at a fixed location. The WTRU will move the coverage area of the AP. When the WTRU first enters the coverage area of a particular AP, the WTRU acquires an association with that particular AP. When the WTRU moves out of the coverage area of the specific AP, the WTRU acquires a new association with another AP and the association with the specific AP is terminated.

Here, the term "disassociation" means a procedure for notifying the associated AP that the WTRU is no longer connected with the AP. When the WTRU leaves the coverage area of the AP or is turned off for more efficient system management, the WTRU is disassociated with the AP. However, in the current IEEE 802.11 standard for wireless LAN (WLAN), this deassociation procedure is only an option. Thus, a manufacturer may or may not apply an association release procedure to a WTRU used for a WLAN.

In order to resolve execution performance issues in allowing association with a new WTRU, the AP may determine the grant in real time by applying an admission control procedure or by applying Radio Resource Management (RRM). do. At this time, the AP monitors the status of used resources as well as the WTRUs associated with it.

However, in the current IEEE 802.11 standard, it is difficult for an AP to monitor the disassociation of a WTRU. Thus, the AP does not have accurate information about the resource and WTRU association status. As a result, the AP is likely to make inaccurate decisions regarding admission control and RRM. This affects the degradation of the WLAN.

Thus, what is needed is a method and system in which an AP can manage association and disassociation of a WTRU in a WLAN.

The present invention relates to a method and system for managing association and disassociation of an AP of a WTRU in a wireless communication system. If the AP detects the WTRU inactivity for a certain time, the AP sends an association confirmation request message to the WTRU. If the AP receives an acknowledgment (ACK) response to the association confirmation request message, the AP maintains an association with the WTRU. However, if the AP fails to receive the ACK, the AP disassociates with the WTRU. The present invention enables the AP to further refine request admission control and RRM decisions with accurate information.

The present invention will be described in more detail with reference to embodiments described below as examples and the accompanying drawings.

Here, "WTRU" includes, but is not limited to, various types of devices operable in a user device, wireless station, fixed or mobile subscriber device, pager, or other wireless environment. In addition, "AP" includes, but is not limited to, various types of interface devices operating within a base station, Node-B, site controller, or other wireless environment.

Embodiments of the present invention may be implemented in an integrated circuit (IC) or in a circuit including a plurality of interconnected components.

1 is a block diagram of a wireless communication system 100 operating in accordance with the present invention. The system 100 includes a plurality of APs 104 and WTRUs 102. The AP 104 periodically sends a beacon message that conveys a plurality of wireless communication parameters. The WTRU 102 receives a beacon message and attempts to associate with one AP selected from the plurality of APs 104. Typically, the selected AP is the AP of the strongest beacon signal. Each AP 104 has a table of WTRUs 102 with which the AP 104 is associated. The AP table is updated periodically or aperiodically.

2 is a flow diagram of a process 200 including method steps for managing association and disassociation of the WTRU 102 in accordance with a first embodiment of the present invention. At step 202, the WTRU 102 establishes an association with the AP 104.

At step 204, the AP 104 monitors transmissions from the WTRU 102 to detect inactivity of the WTRU. Preferably, the inactivity state is determined by setting a timer. The AP sets a timer each time it receives a transmission from the WTRU. An inactivity state is detected when the timer expires without receiving any transmission from the WTRU.

At step 206, when the AP 104 detects an inactivity state of the WTRU 102, the AP 104 sends an association confirmation request message to the WTRU 102. At the same time, the AP 104 sets a timer for ACK from the WTRU 102. When the WTRU 102 receives the association confirmation request message, it must respond with an ACK to maintain association with the AP 104. At step 208, the AP 104 determines whether an ACK has been received before the timer expires. At step 210, if the AP 104 does not receive an ACK before the end of the timer, the AP 104 disassociates with the WTRU 102. At step 212, if the AP 104 receives an ACK before the timer expires, the association with the WTRU 102 is maintained. After the AP 104 receives an ACK from the WTRU 102, the process 200 returns to the step labeled 204 to monitor the status of the WTRU 102.

3 is a block diagram illustrating message exchange between the AP 104 and the WTRUs 102a and 102b. In FIG. 3, two WTRUs 102a, 102b were previously associated with the AP 104, but both WTRUs 102a, 102b are currently inactive. After detecting that both WTRUs 102a and 102b are inactive, the AP 104 sends an association confirmation request message 302 and 304 to the two WTRUs 102a and 102b, and the two WTRUs 102a and 102b. The timers 312 and 314 are set for each. The WTRU 102a is within the coverage area of the AP 104 and wants to remain associated with the AP 104. However, the WTRU 102b does not currently want an association with the AP 104 or the association confirmation message 304 is unreceivable. Accordingly, the WTRU 102a sends an ACK 306 to the AP 104 before the timer 312 ends. However, the AP 104 does not receive an ACK from the WTRU 102b before the end of the timer 314 set for the WTRU 102b. Thus, the AP 104 disassociates with the WTRU 102b and releases the radio resources previously designated for the WTRU 102b. Further, the AP 104 sets a timer 312 that tracks the passage of time after receiving the ACK 306 from the WTRU 102a. If the AP 104 detects that the inactivity state of the WTRU 102a has elapsed a predetermined time, the AP 104 sends another association confirmation request message 308 to the WTRU 102a. The AP 104 receives another ACK 310 from the WTRU 102a and maintains an association with the WTRU 102a.

4 is a flow diagram of a process 400 including method steps for managing association and disassociation of the WTRU 102 in accordance with another embodiment of the present invention. At step 402, the AP 102 broadcasts an association confirmation period, preferably over a beacon channel. The WTRUs 102 associated with the AP 104 receive a beacon message that includes an association confirmation period via a beacon channel, and transmit this beacon confirmation period to the Management Information Base (MIB) of the WTRU 102. Save it. When the WTRU 102 is in an inactive state, the WTRU 102 sends an association confirmation message to the AP 104 every association confirmation period.

4, the WTRU 102 establishes an association with the AP 104 at the step indicated at 404. As described above, the AP 104 monitors the transmission status of each WTRU 102 to determine whether the WTRU 102 is in an operational state. Therefore, in this embodiment, as in step 406, whenever the WTRU sends a message to the AP 104, the AP 104 and the WTRU set a timer. In order to maintain the association state, the WTRU must send an association confirmation message before the timer expires. At step 408, the AP 104 determines if there is an association confirmation message from the WTRU. If the AP 104 does not receive an association confirmation message before the timer expires, the AP 104 disassociates with the WTRU at step 410. If the AP 104 receives an association confirmation message before the timer expires, the AP 104 remains associated with the WTRU at step 412 and the process returns to step 406.

5 is a signal flow diagram illustrating message exchange between the AP 104 and the WTRUs 102a and 102b according to another embodiment of the present invention. The AP 104 broadcasts the association confirmation period P, preferably via beacon messages 502a and 502b. WTRUs 102a and 102b are associated with the AP 104 but are in an inactive state. The two WTRUs 102a and 102b receive the beacon messages 502a and 502b and set an association confirmation period in the management information base MIB of each WTRU 102a and 102b. The AP 104 and the WTRUs 102a, 102b set a timer 508a.

The WTRU 102a is within the coverage area of the AP 104 and desires to maintain association with the AP 104. However, the WTRU 102b does not currently need to be associated with the AP 104. Thus, the WTRU 102a sends an association confirmation message to the AP 104 before the timer 508a expires, but the WTRU 102b does not. Upon receiving the association confirmation message 504, the AP sets a timer 508b. However, as noted above, the AP 104 does not receive an association confirmation message from the WTRU 102b before the timer 508a expires, and the AP 104 disassociates with the WTRU 102b and assigns it to the WTRU 102b. Freed resources If the WTRU 102a continues to be inactive, the WTRU 102a should periodically send an association confirmation message 506 before the message timer 508b. While the AP 104 receives the association confirmation message 506 from the WTRU 102a, the AP 104 remains associated with the WTRU 102a even though the WTRU 102a is inactive.

Preferably, when the WTRU 102b is out of coverage area of the AP 104, associated with another AP 104, or in a state in which the association with the AP 104 is no longer needed, such as in a powered off state, The WTRU 102 sends an association disassociation message 510. The transmission of this disassociation message 510 is preferably a mandatory message. When the AP 104 receives the disassociation message 510, the AP 104 disassociates with the WTRU 102b and releases the radio resource assigned to the WTRU 102b.

6 is a block diagram of a system 600 for managing association and disassociation of the WTRU 102 in accordance with the present invention. System 600 includes an AP 104 and a WTRU 102. The AP 104 includes a transceiver 106, a state tracking device 108, and a controller 110. The WTRU 102 includes a transceiver 112 and a controller 114. The transceiver 106 of the AP 104 sends and receives messages with the WTRU 102. The state tracking device 108 tracks the associative and operational states of each WTRU 102 associated with the AP 104. The AP 104 has, in memory 111, a WTRU table of the WTRU 102 with which the AP 104 is associated. If a new WTRU 102 is associated with the AP 104 or an existing WTRU 102 is unassociated, the AP 104 updates the WTRU table in the memory 111. The state tracking device 108 continues to monitor the transmission from the associated WTRU 102 and determines whether the WTRU 102 is operational. If there is no data transmission for a fixed time, it is treated as inactive. When the inactivity state is detected, the controller 110 of the AP 104 sends an association confirmation request message to the WTRU 102. The controller 110 also determines whether an ACK has been received from the WTRU 102. If not, the controller 110 removes the WTRU 102 from the WTRU table in the memory 111. The transceiver 112 of the WTRU 102 sends and receives messages with the AP 104. The controller 114 controls the overall procedure for obtaining and maintaining association and disassociation with the AP 104. The WTRU 102 receives an association confirmation request message from the AP 104, and the controller 114 sends an ACK to the AP 104 if it wants to continue to associate with the AP 104.

In one embodiment, the controller 110 of the AP 104 broadcasts an association confirmation period in a beacon message, and the WTRU 102 further includes a state tracking device 116. When the WTRU 102 is in an inactive state, if the AP 104 does not receive an association confirmation message from the WTRU 102 within the association association period above, the controller 110 may request a WTRU (from the WTRU table in the memory 111). 102) is removed. The state tracking device 116 of the WTRU 102 determines the state of the WTRU 102 by monitoring the transmission from the WTRU 102. If the state tracking device 116 determines that the association confirmation cycle will end after the last transmission from the WTRU 102, the controller 116 sends an association confirmation message if the WTRU 102 wishes to maintain association with the AP 104. It transmits to the AP 104 every association confirmation period broadcast through the beacon channel.

In another embodiment, if the WTRU 102 determines that there is no need to maintain an association with the AP 104, the controller 114 sends an association release message to the AP 104. When the AP receives an association disassociation message from the WTRU 102, the controller 110 of the AP 104 disassociates the WTRU 102.

Although the features and components of the present invention have been described in particular combinations of the preferred embodiments, each of these features and components may be used alone without the other features and components of the preferred embodiments, and other features and features of the present invention. It can be used in various combinations with the components or separately.

According to the system of the present invention, it becomes possible for an AP to manage association and disassociation of a WTRU in a wireless LAN.

1 is a block diagram of a wireless communication system including an access point (AP) and a wireless transmit / receive apparatus (WTRU) operating in accordance with the present invention.

FIG. 2 is a flow diagram illustrating a procedure for managing association and disassociation of the WTRU of FIG. 1.

3 is a signal flow diagram illustrating message exchange between an AP and a WTRU in the system of FIG.

4 is a flowchart illustrating a procedure for managing association and disassociation of a WTRU according to another embodiment of the present invention.

5 is a signal flow diagram illustrating message exchange between an AP and a WTRU according to another embodiment of the present invention.

6 is a block diagram of a system for managing association and disassociation of a WTRU in accordance with the present invention.

Claims (8)

As an access point, A state tracking device configured to detect an inactivity state of a WTRU for the AP, the state tracking device configured to transmit and receive signals to / from a controller; Broadcast the association confirmation period, the controller configured to disassociate the WTRU if the AP does not receive an association confirmation message from the WTRU within an association confirmation period; An inactive state of the WTRU is detected by the state tracking device, An expiration of the association confirmation period for each WTRU is determined by a timer for each WTRU that is initiated each time the AP receives an association confirmation message from each WTRU. The method of claim 1, And the state tracking device detects an inactivity state of a WTRU when the AP does not receive an association confirmation message within the association confirmation period. The method of claim 2, The AP periodically transmits an association confirmation request message to WTRUs in an inactive state. The method of claim 3, wherein The AP is configured to broadcast the association confirmation period over a beacon channel. A wireless transceiver (WTRU), A state tracking device configured to detect an inactivity state of the WTRU for at least one access point (AP), the state tracking device configured to transmit and receive signals to / from a controller; The controller configured to send an association confirmation message to the AP every association association period when the WTRU needs to remain inactive or associated with the AP, The inactivity state of the WTRU is detected by the state tracking device, And the association confirmation period is tracked by a timer in the WTRU that is initiated each time the WTRU sends an association confirmation message to the AP. The method of claim 5, wherein And when the WTRU enters an inactive state for an AP, the state tracking device transmits a signal to the controller indicating that the WTRU has become inactive for the AP. The method of claim 5, wherein The WTRU further comprises a management information base configured to store the association confirmation period. The method of claim 5, wherein And the WTRU is configured to receive the association confirmation over a beacon channel.