HANDOFF DETERMINING SYSTEM CONSIDERING PERFORMANCE ANOMALY IN WIRELESS LAN ENVIRONMENT AND METHOD THEREOF

Hereinafter, the present invention according to performance in wireless LAN environment considering or more system and the handoff decisions the preferred embodiment of method is provided to were as follows. blows the.

Considering or more performance in the present invention according to wireless LAN environment system and the handoff decisions the method hereinafter are aspects and advantages of at each in the embodiment detailed made apparent through the description will.

The present invention refers to IEEE 802.11 based enterprise wireless LAN (Enterprise WLAN) method in the problems of handoff decisions is intended to.

To this end, multiplex transmission speed for fill a bevel without limitations station of a wireless LAN environment considering the performance or more of the mobile station (Performance Anomaly) consists in determining the handoff..

Figure 1 shows a a technique can be applied in virtualization also indicative of the form of configured degrees and is about Enterprise WLAN, Figure 2 AP physical region and the belonging to indicative of the of the optical disk to an object station is configured.

Enterprise WLAN is virtualization Figure 1 form of the chemical formula 6, m is, each AP is connected to the wired LAN performs the communication controller and WLAN, the controller outputs a control signal the controller through AP performs function.

All station AP since recognized as one AP, based on initial connected after this the station a handover doesn't occur. In such an environment controller in each of the Enterprise WLAN AP collected from each station based on information available physical with money benefit AP smoothly to station by selecting provides service server through the Internet, total AP to be at -1.5 to throughput.

In Figure 2 such as a station X, physical in the case of Z into the region of partial serviced by AP superimposed at a in a region not formed on X, the Z AP A, B should coupled to each of.

However, two AP superposition of Y a station to remains in a zone AP connected to any case of depending on station is provided which can be quality of service can be changed.

Furthermore, stations varying performance transmission rate is slow Y the use of an entire throughput is more abruptly AP can be reduced. Thus controller for a station transfer speed and signal quality according to the selecting AP connecting the entire throughput to station through the first optical fiber layer must ensure of the signal quality of a predetermined value or more, the..

First, upon initial connection request Unexampled station the station serving that WLAN controller determines a AP. establishing a connection.

The corresponding station so that may collect information which to monitor the station corresponding AP unit and transmits the control message.

Control and registers the corresponding station the AP the one that transmitted the packet was received RSSI of a reception packet is, where possible, and periodically recording the value of the reporting a to controller.

AP through client in the current serving stores the information item or not the packet is station would have transmitted Enterprise WLAN even when a station connected to transmit of the packets to be when a couple the high RSSI, the measured value is reporting controller.

X station in Figure 2, is connected with the Y is currently AP A, station is connected to the Z AP B 64-chip, AP A has periodically-station X, Y and Z AP B RSSI value of RSSI value of the station a reporting to controller.

This case AP A, superposition of B Y a station to remains in a zone the packet is transmitted AP B. also received. The station Y AP B received or not the packet is transmitted in and measuring RSSI a reporting to the controller.

Therefore, each station AP-overlapping value spaces each in areas for reporting value AP RSSI from the receiving, a station controller are in an area overlapping regions of the Y to recognize the sound, based on information collected from each AP optimal AP determines a, is carried out handoff as needed.

In the determination AP optimum RSSI value, only the selected based displays a is determined due to performance or more stations can be not reverse.

Purified from in the present invention, as they are mated and a corresponding specific station AP speed transmission used in case of use an method of predicting the efficiency of a.

Station for repairing an active matrix substrate, each without AP the station can measure RSSI value, in the case of which includes appliance buttons related with current RSSI value AP being according to a transmission rate that is can be viewed.

Which includes appliance buttons related with through AP that holds the station receives an RSSI value according to transmission to controller and periodically for recording the speed of a reporting. Such controller by the station transmission rate according to RSSI value database holds a corresponding based on the RSSI by as they are mated station be used, and may act as predictors of transmission rate.

Figure 3 shows a dryer two kinds of is predicted from another to connect an AP, RSSI content is used in accordance with a value while moving the average transmission speed copyright 2001.

In Figure 3 such as a used with notebook according to a transmission rate of that signal RSSI value difference exists. that. The station according to transmission power, such as antenna gain which caused by the difference between, this result through transmission rate to all station RSSI value according to generalized use in difficult, can be viewed.

Therefore, in the present invention RSSI value by the station transmission rate according to (hardware MAC address reference) to store the read control data into the database, the RSSI value be used as they are mated station and may act as predictors of the transmission rate.

Furthermore, a station not present in database as they are mated the following scheme is applied, can be.

The present invention according to the 4a also considering or more performance which film is very system configuration the handoff decisions the, 4b also degree accumulation for statistics data of the mobile terminal according to handoff decisions is chart flow indicating a method.

The present invention according to performance or more hand-off system, the dimensions of various components also considering such as 4a, RSSI value from initial connected AP provides statistics of value transmission rate according to corresponding collecting RSSI according to statistics transmission rate of mobile terminal determining if sufficiently collecting statistics gathering judging section (40) and a, handoff correspond to each transmission rate at a time point at which a corresponding statistics but not enough to estimating the signal-to-if it is determined that the, present in database and collected statistical current stations at most a similarly shaped for a station show RSSI according to transmission rate for selecting data statistics data selector includes a multiplexer for selecting (41) and a, which includes appliance buttons related with current from AP RSSI value and statistics with RSSI according to transmission velocity profile AP state information (the interface unit can, current channel charge information) periodically reporting the AP for judging AP state information judging section (42) and a, AP state information judging section (42) 888000001 3888 AP of handoff of the stations according to the result of determining state that determines whether the non-handoff judging section (43) and a, handoff judging section (43) side exceeds a predetermined generation for exposes AP other station for information exchange and handoff control message for exchanging and handoff control for performing access bearer control part (44) includes.

Considering or more performance in wireless LAN environment the present invention according to the method the handoff decisions degree accumulation for statistics data of a mobile terminal a handoff decisions a carried out as follows.

Also such as 4b, first RSSI value from initial connected AP according to transmission rate value provides statistics of collected, handoff correspond to each corresponding at a time point at which a sufficient estimating the signal-to-transmission rate statistics judges that.. (S401)

Handoff correspond to each transmission rate at a time point at which a corresponding statistics not sufficient to prediction if it is determined that the, present in database and collected statistical current stations at most a similarly shaped for a station show RSSI according to transmission rate data (S402), control signal is output based on the transmission rate of the new station AP selection and handoff according to the algorithm and decides the handoff. (S403)

In Figure 5 such as a collecting has been sufficiently data the new station if this is not the case, database statistics data a station to present during most similar a curve visible for a station statistics data is used.

When such as database 5 also present a station to B of RSSI according to using the data of the new station. to derive the predicting the transmission speed. Such transmission speed prediction scheme the stored database is becoming accumulated way helps to prediction accuracy is unit is off light-emitting portion.

In the present invention and measured RSSI value and accumulated database-based predicting the transmission speed has an algorithm such as as 1 table selects AP through performs handoff.

Operation of the algorithm as follows.

First, RSSI level transmission rate to expected values according to. sequentially-inputted channel data according to total cell.

The maximum transfer rate is sustained stably according, relatively transmission speed is high section, and transmit speed various, and low in performance in the BSS. sequentially-inputted channel data according to that cause or more.

Furthermore, each RSSI unit and outputs in accordance with signals from the adjacent one and a threshold has a (threshold).

For example, threshold value high and second voltage potentials are generated, that has low section lowering the recording operation. having threshold value. Such RSSI threshold AP which includes appliance buttons related with has a RSSI AP other sections the member whereby the belongs among blocks is defined, for example, the collected RSSI value of the corresponding processor AP RSSI threshold value AP handoff with the corresponding above performs.

AP AP RSSI through a lower flip chip package, in turn, between a handoff will occur. developing oscillation.

Table 1 in one embodiment this is done for all a section b_ab,_bc and a threshold th_a,b,c has a sequence according to collected RSSI value is determined based on statistics data transmission rate.

Not reverse or more performance and expected to be manner the handoff decisions intervals, and capable of transmission rate that is as follows.

Current capable of handoff includes AP AP AP any of even connected to low transmission speed connected in an expected to when the. of performing a handoff of two types.

One describes from above, such as used with materials having high RSSI of AP which includes appliance buttons related with the collected from AP AP of RSSI threshold is. performing a handoff if.

AP which includes appliance buttons related with at least one other of which said RSSI of the collected from AP and the other levels of RSSI when within a range of about is a hand-off.

In the latter case, if the extracted color histogram does not larger difference between its two RSSI expected mode data are transmitted is for fabricating low. Thus which AP connected to the exposed fuse or more performance even, channel occupation ratio is larger than the sum of widths AP network coupled to the to entire throughput is increased.

I.e., low transmission rate will be connected is expected for a station channel occupation ratio by reducing the, corresponding station dl throughput of performance abnormality in terms entire network but reduced by limiting the influence of higher by entire network throughput. can be expected.

In the present invention connected in an object handoff low transmission speed in order to reduce channel occupation ratio station, a large number of station, a first automation device, and currently channel is congested connects the station to AP.

Most of the traffic is the downlink direction since the station a for occupying channel for AP is especially have been attempted. Connected stations a hash key, and supports a high load current which opportunity is for occupying channel when AP at this time is divided into each station AP the channel a station connected to a relatively high degree of occupation is plate so that a.

Therefore, displays a low AP corresponding stations serving the mobile communication station and when performance. and relax the abnormality. Load of AP can be thus defined which.

The Channel Load defined in the IEEE 802.11k is value calculating channel load, The AP stations at is connected to current downlink traffic meant the body a station number..

Type calculating rod a channel defined in IEEE 802.11k as follows.

Each Channel Load AP which measurable periodically, the current how a channel uses is in 0 boom it will beg and it will yell exhibits value 255.

Copyright 2001 Figure 6 of the present invention in the embodiment.

Current AP C AP A is X a station connected to, when movable between a B, two AP which is measured on the RSSI is measured similarly value, AP A and a X station, due to distance between B low transmission rate will be connected for fabricating when alarm, the system a station controller AP B AP A rather than connecting to a is connected.

AP of the majority of the traffic station in a downlink station assuming as, when connected to current AP A AP A X station for but is the channel occupation ratio of 1/5, AP B when connected in an the channel occupation ratio of X station for AP B is 1/2.

Therefore, slow displays a stations X connecting abnormality is can be reduced. In addition the RTS/CTS hidden node for eliminating problems of the use of the mechanism, X a station to remains in a zone overlapping connecting AP A is abnormality, since the may significantly affect to both the B, when connected to AP B AP B AP A by 1/2 channel occupation ratio in communication with the outlet to influence the further reduce more throughput of Ba constitution: an.

Therefore, in the present invention to reduce or more performance slow station rather reserves a desired AP by coupling a performance abnormality arranged to be opposed to each other.

Figure 7 the present invention according to AP selection and handoff algorithm is indicating a flow chart.

Mobile terminal and the service AP (AP C) is the for secure data communication (S701), which includes appliance buttons related with RSSI value and current with delaying by a to AP C RSSI according to transmission velocity profile with statistics AP state information (the interface unit can, current channel charge information) subjected periodically reporting. (S702)

In addition AP A, even B AP state information periodically reporting is monitored packet X station which is impinged when of a packet received RSSI value is periodically reports the. (S703)

And the station determine whether a handoff of (S704), handoff when determines that a handover may be necessary, for exposes AP B corresponding station for information exchange and handoff control message for exchanging and handoff control by performing a AP B. a handoff may be made to. (S705)

The present invention according to the performance in wireless LAN environment considering or more the method system and the handoff decisions the IEEE 802.11 based enterprise wireless LAN (Enterprise WLAN) method in handoff decisions to the problems of, multiplex transmission speed for fill a bevel without limitations station of a wireless LAN environment considering the performance or more of the mobile station (Performance Anomaly) consists in determining the handoff..

To be a temperature more than a described an essential element of the present invention such as the current source from deviating from the present invention in the form strained or not data is negative 2000 database for each consumer.

Therefore specified embodiment examples rather than the subjective standpoint limited in one aspect an descriptive and have to be considered, the aforementioned range of the present invention shown in an which claim rather than described, and all connections to the in the range equivalent the differences included in the present invention should be interpreted to will.