KR101351662B1 - Apparatus and method for searching access point in wireless communication system - Google Patents

Abstract

The present invention provides a method for searching for an AP in a wireless communication system, the method comprising: searching for a neighboring AP (access point) in a preset area based on location information obtained through a location information module; Re-queue the AP having the highest reception power based on the acquired location information with the highest priority, and mapping the received electric field strength value and the identification information of the liquefied neighbor AP based on the obtained location. Generating a map, accessing a channel with the AP of the highest priority, and performing a handoff based on the generated map when a handoff occurs while performing wireless communication through the accessed AP. Characterized by including the process.

Description

APPARATUS AND METHOD FOR SEARCHING ACCESS POINT IN WIRELESS COMMUNICATION SYSTEM

The present invention provides a wireless communication that reduces the number of AP searches based on a map generated based on current location information acquired through a global positioning system (GPS) when a handoff occurs between a mobile station and an access point (AP) in a wireless communication system. The present invention relates to an AP discovery apparatus and method in a system.

As location-based services grow significantly, a location-aware / tracking system is available that can track the location of the target using technology that can capture location information, such as GPS, and tags that include wireless communications, such as Wi-Fi. It is emerging.

Applications of real-time location tracking systems are used to measure the location of people or objects such as beaches, amusement parks, and logistics environments.

Such a location tracking system is a system for identifying the location of a target tag. The location tracking of the tag collects location information through the location tracking system and delivers the collected information to the user through the wireless AP.

In a location tracking system, the tag uses a location determination system such as GPS to collect location information. The collected location information is transmitted through a wireless AP, such as Wi-Fi, through a wireless AP to which a tag is currently connected. In transmitting information through the wireless AP, as shown in FIG. 2, when the communication distance with the connected AP is exceeded or an obstacle exists, a communication disconnection occurs and a handoff is performed to connect to a new AP.

Due to the characteristics of a mobile station, a mobile station frequently moves, and thus a lot of handoff occurs between the wireless terminal and an access point (AP). Repeated authentication every handoff incurs a lot of overhead for many wireless domains and terminals.

In addition, in performing the handoff, the IEEE 802.11 standard uses a method of searching for neighboring APs again and again, which causes a lot of power consumption and connection disconnection time.

To solve this problem, there has been a handoff method for connecting to a new AP before disconnection occurs, but there is no way to focus on reducing power consumption.

Accordingly, the present invention is limited by reducing the number of AP searches based on a map generated based on the current position information acquired through the Global Positioning System (GPS) when a handoff occurs between a mobile station and an AP in a wireless communication system. In addition to reducing power consumption by searching for neighboring APs whenever a handoff occurs, the mobile terminal with power can also continuously update valid information on APs that can be handed off based on the current location of the mobile terminal. By maintaining the map, we want to provide a technology that can contribute to the improvement of the quality of location-based services.

According to an aspect of the present invention, in the AP search method in a wireless communication system, searching for a neighboring AP (Access Point) in a predetermined area based on the location information obtained through the location information module, and at least two of the searched Re-queue the above-mentioned neighboring APs with the highest priority of the AP having the maximum reception power based on the obtained position information, and each received electric field strength value of the liqueured neighboring APs based on the obtained position. And a process of generating a map to which the identification information is mapped, forming a channel to the corresponding AP of the highest priority, and accessing, and based on the generated map when a handoff occurs while performing wireless communication through the accessed AP. And performing a handoff.

According to another aspect of the present invention, in an AP search apparatus in a wireless communication system, a location information module for acquiring current location information and a neighboring AP (Access) within a preset area based on the location information acquired through the location information module An AP search unit for searching and outputting a point), a mapping unit for generating a map of received electric field strength values and identification information of the neighboring APs detected by the wireless communication unit based on the obtained position, and the AP search unit Re-queue at least two neighboring APs outputted from the AP with the highest received power on the basis of the position information obtained from the location information module, and the received electric field strength value of each of the liqueured neighboring APs. And a control unit for generating a map to which the identification information is mapped and controlling to form and access a channel with the AP having the highest priority. It is gong.

When the handoff occurs due to the movement of the mobile terminal, the present invention first searches for valid information from a pre-generated map and performs handoff to the corresponding AP without needing to search for a neighbor AP at a changed location. By updating the information obtained through the search for neighbor AP at the changed location to the previously generated map, the mobile terminal with limited power searches for the neighbor AP whenever a handoff occurs and reduces power consumption. By maintaining a pre-generated map that can continuously update the valid information on the handoffable AP based on the current location, there is an effect that can contribute to the quality improvement of the location-based service.

1 is a schematic configuration diagram of an entire system for AP search in a wireless communication system according to an embodiment of the present invention.
2 is a flowchart illustrating a method for searching for an AP in a wireless communication system according to an exemplary embodiment of the present invention.
3 is a flowchart illustrating an operation of forming and accessing a channel to an AP when a handoff occurs in a mobile station according to an embodiment of the present invention.
Figure 4 is an exemplary view schematically showing the overall operation of the AP search method in a wireless communication system according to an embodiment of the present invention.
5 is a detailed block diagram of an AP discovery apparatus in a wireless communication system according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be appreciated that those skilled in the art will readily observe that certain changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. To those of ordinary skill in the art.

The present invention searches for neighboring APs in a network based on current location information acquired through a global positioning system (GPS) when a handoff occurs between a mobile station and an access point (AP) in a wireless communication system, and searches for each of the found APs. The identification information and the RSSI (Received Signal Strength Indicator) value from each AP to generate a map, and then form a channel to the AP corresponding to the highest priority in the generated map to perform wireless communication. When a handoff is generated due to the movement of, the neighbor AP at the changed location is not searched, and the effective information is first searched from the previously generated map to perform a handoff to the corresponding AP. When the mobile terminal with limited power is handed off by updating the information obtained through the AP discovery to the previously generated map. It not only reduces power consumption by searching for neighboring APs, but also improves the quality of location-based services by maintaining a pre-generated map that can continuously update valid information on handoffable APs based on the mobile terminal's current location. To provide technology that can contribute to

In addition, the mobile terminal according to an embodiment of the present invention may be a digital broadcasting terminal, a personal digital assistant (PDA), a smart phone, a tablet PC, an iPad, an example of a 3G terminal. For example, all information communication devices such as International Mobile Telecommunication 2000 (IMT-2000) terminals, Wideband Code Division Multiple Access (WCDMA) terminals, Global System For Mobile Communication Packet Radio Service (GSM / GPRS), and Universal Mobile Telecommunication Service (UMTS) terminals. And multimedia devices. However, it will be understood by those skilled in the art that the configuration according to the embodiments described herein may be applied to a fixed terminal such as a digital TV, a desktop computer, and the like, unless the configuration is applicable only to a portable terminal.

Hereinafter, an AP search in a wireless communication system according to an embodiment of the present invention will be described with reference to FIG. 1.

1 is a schematic configuration diagram of an entire system for AP search in a wireless communication system according to an embodiment of the present invention.

As shown in FIG. 1A, the system 100 to which the present invention is applied includes a movement for receiving current location information from at least one GPS 10, 12, 14 and the GPS 10, 12, 14. A wireless communication service is provided to a mobile station 110 in a corresponding network through a terminal 110, a wireless Internet of the mobile terminal 110, for example, one or more APs 112 for providing a Wi-Fi function, and the AP 112. It includes a service management server 114 and a plurality of user terminals (116, 118) connected to the service management server 114, referring to Figure 1 (b), the mobile terminal is moved from the previous position When reaching the current position, if the distance exceeds the communication function distance with the previous AP 1 or the obstacle exists, the communication is disconnected and a handoff is performed.

In this case, the operation of the AP search method in the wireless communication system according to the present invention according to the handoff will be described in detail with reference to FIG.

2 is a flowchart illustrating a method for searching for an AP in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, first, current location information is acquired through a location information module in step 210, and a neighboring AP (access point) within a preset area is searched based on the obtained location information in step 212.

In step 214, the at least two neighboring APs retrieved in step 212 are re-queueed to the AP having the highest reception power based on the obtained location information. In step 216, a map is formed in order from the AP having the highest priority at the maximum reception power at the current location of the mobile terminal. That is, a map in which each received electric field strength value and identification information of the liqueured neighboring AP are mapped based on the obtained position is generated.

In step 218, a wireless communication is performed by forming a channel to the corresponding AP having the highest priority in the generated map.

Thereafter, in step 220, the mobile station checks the handoff caused by the movement or failure of the mobile terminal, and if a handoff occurs, the mobile station moves to step 222 to acquire location information at the current location.

In step 224, it is checked whether the acquired location information is valid location information existing in the previously generated map, that is, the map generated in step 216. If there is valid location information in a preset area in the pre-generated map, the process proceeds to step 226 to select an AP according to the information mapped to the pre-generated map, and performs access to the selected AP to perform wireless communication. Do this.

That is, the process of selecting the AP may search for location information close to the current location information from a pre-mapped map and compare the searched location information with the current location information within a preset area range as a result of comparing / contrasting the searched location information. The AP that forms and accesses the AP is selected as an accessible AP.

On the other hand, as a result of performing step 224, when there is no valid location information in the preset area based on the current location information, the neighboring AP in the preset area is searched based on the location information in step 228, and the searched at least two or more in step 230 A neighbor AP is queried with priority of an AP having a maximum reception power based on the acquired location information, and the received electric field strength of each of the queried neighbor APs is based on the acquired position in the previously generated map in step 232. The map is mapped with the value and the identification information, and a channel is accessed from the updated map to the corresponding AP having the highest priority.

Here, an operation of forming and accessing a channel to the AP due to the handoff of the mobile terminal will be described in detail with reference to FIG. 3.

The mobile station 310 requests channel state information (CSI) in a corresponding network based on the AP of the highest priority from the currently serving base station, and selects a channel having excellent channel gain through the requested CSI. Then, the handoff request message is transmitted to the corresponding AP 314 through the selected channels (S316 and S322), and correspondingly, a response message is received from the corresponding AP 314 (S318 and S322).

Thereafter, a request message for authentication is transmitted through a channel that receives the response message from the AP 314 (S324), and correspondingly, a response message is received from the corresponding AP 314 (S326). After performing the authentication procedure, a request message for connection to the AP 314 is transmitted (S328), and correspondingly, after receiving a response message from the AP 314 (S330), the hand to the AP 314 is transmitted. Perform off.

FIG. 4 schematically illustrates the operations 210 to 232. First, referring to FIG. 4A, the mobile terminal 412 currently attempting to perform a handoff to AP 3 has an AP at a previous location A. FIG. The history of wireless communication with 1 and the history of wireless communication with AP 2 at the previous location B are mapped with the received electric field strength value and corresponding AP identification information at the corresponding location together with the location information obtained from the mobile terminal 412. The map is generated in the form as shown in 410, and referring to FIG. 4B, the mobile terminal detects whether the location information acquired at the current location C is valid information in the previously generated map, that is, searches for nearby location information. In the absence, that is, when the location information acquired at the current location C corresponds to location information that exists outside an effective reference distance that is not close to the location information mapped on the previously generated map, the location information acquired at the current location C And updates the map generating groups to the new mapping information in addition to the map generating group identification information for the AP 3 to perform a received signal strength value and a hand-off in the obtained position.

In the above, the AP discovery method in the wireless communication system according to an embodiment of the present invention has been described.

Hereinafter, an AP discovery apparatus in a wireless communication system according to an embodiment of the present invention will be described in detail with reference to FIG. 5.

5 is a detailed block diagram of an AP discovery apparatus in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 5, in the wireless communication system according to an exemplary embodiment, the AP search apparatus 500 may include a wireless communication unit 510, a location information module 512, a controller 514, an AP search unit 516, and the like. The mapping unit 518 is included.

The wireless communication unit 510 includes Rx and Tx and performs communication with a base station and an AP by using a wireless up / down signal. That is, a wireless downlink signal is received from the air by using an antenna, and downlink data obtained by demodulating the wireless downlink signal is output to the controller 514. In addition, the wireless communication unit 510 modulates uplink data input from the control unit 514 to generate a wireless downlink signal, and wirelessly transmits the generated wireless uplink signal to the air using an antenna.

The location information module 512 obtains and outputs current location information from a GPS satellite.

The AP search unit 516 searches for and outputs a neighboring AP (Access Point) in a preset area based on the location information obtained through the location information module.

The mapping unit 518 generates, as a map, received electric field strength values and identification information of the neighboring APs detected by the wireless communication unit based on the obtained position.

The controller 514 re-queues at least two neighboring APs output from the AP search unit 516 to the AP having the highest reception power based on the position information obtained from the position information module. And generating a map in which each received electric field strength value and identification information of the liquefied neighboring AP are mapped, and forming a channel to access the AP having the highest priority.

The controller 514 searches for valid location information in a preset area based on the current location information, and controls to select an AP according to the information mapped to the retrieved location information.

In this case, the AP selection retrieves location information close to the current location information from a pre-mapped map, and forms a channel from the searched location information if the searched location information is included in a preset area range as a result of comparing / contrasting the current location information. Select the accessed AP as an accessible AP.

In addition, the controller 514 searches for the neighboring AP in the preset area based on the location information in the absence of valid location information in the preset area based on the current location information, and retrieves the searched at least two neighboring APs. Re-queue the AP having the maximum reception power based on the location information at the highest priority, and the received electric field strength value and the identification information of the liqueured neighboring AP are based on the obtained location on the previously generated map. The mapped map is updated, and a channel is controlled to be accessed by the AP having the highest priority in the updated map.

The controller 514 requests channel state information (CSI) in a corresponding network based on the AP of the highest priority to the currently serving base station, and provides a channel having excellent channel gain through the requested CSI. And screens a handoff request message to the corresponding AP through the selected channels, receives a response message from the corresponding AP in response to the selected AP, and performs authentication through a specific channel among the selected channels.

In the wireless communication system according to the present invention as described above, the operation of the AP search apparatus and method can be made, while in the above description of the present invention has been described with respect to specific embodiments, various modifications without departing from the scope of the present invention Can be implemented. Accordingly, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by equivalents of the claims and the claims.

510: wireless communication unit 512: location information module
514: control unit 516: AP search unit
518: mapping unit

Claims (10)

In the AP search method in a wireless communication system,
Searching for a neighboring access point (AP) in a preset area based on the location information acquired through the location information module;
Re-queue the searched at least two neighboring APs with the highest priority of the AP having the maximum reception power based on the obtained location information;
Generating a map to which received field strength values and identification information of the liquefied neighboring APs are mapped based on the obtained position;
Forming and accessing a channel to the AP having the highest priority;
Performing a handoff based on the generated map when a handoff occurs while performing wireless communication through the accessed AP;
When performing the handoff,
Searching for valid location information in a predetermined area based on current location information from the generated map and selecting an AP according to the information mapped to the found location information; Search method. delete The method of claim 1, wherein when performing the handoff:
Searching for neighboring APs in the preset area based on the location information when there is no valid location information in the preset area based on the current location information;
Re-queue the searched at least two neighboring APs with the highest priority of the AP having the maximum reception power based on the obtained location information;
Updating a map in which each received electric field strength value and identification information of the liquefied neighboring AP are mapped to a previously generated map based on the obtained position;
And forming a channel from the updated map to a corresponding AP having the highest priority and accessing the AP. The method of claim 1, wherein the forming and accessing a channel with the AP comprises:
The mobile terminal requests a current service providing base station for channel state information (CSI) in a network covered by the current service providing base station based on the AP of the highest priority;
Selecting a channel having excellent channel gain through the requested CSI;
Transmitting a handoff request message to the corresponding AP through the selected channels and receiving a response message from the corresponding AP in response thereto;
And a process of performing authentication through a specific channel among the selected channels. The method of claim 1, wherein the selecting of the AP comprises:
Search for location information close to the current location information from the previously mapped map, and if the searched location information and the current location information are included within a preset area range as a result of comparison / contrast, the AP is accessed by forming a channel from the searched location information. AP searching method in a wireless communication system, characterized in that the selection as possible AP. In the AP search apparatus in a wireless communication system,
A location information module for obtaining current location information;
An AP search unit that searches for and outputs a neighboring AP (Access Point) in a preset area based on the location information obtained through the location information module;
A mapping unit configured to generate, as a map, received electric field strength values and identification information of the neighboring APs detected by the wireless communication unit based on the obtained position;
Re-queue the at least two neighboring APs output from the AP search unit to the AP having the highest reception power based on the position information obtained from the location information module with the highest priority, and each of the queried neighboring APs. And a control unit for generating a map in which the received electric field strength value and the identification information are mapped, and controlling to form and access a channel with the corresponding AP of the highest priority.
The control unit,
And searching for valid location information in a preset area based on current location information and selecting an AP according to the information mapped to the searched location information. delete 7. The apparatus of claim 6,
When there is no valid location information in the preset area based on the current location information, the neighboring AP in the preset area is searched based on the location information, and the received power is received based on the acquired location information. Re-queue the maximum AP to the highest priority, update a map to which received electric field strength values and identification information of the liqueured neighboring APs are mapped based on the obtained position on a previously generated map, and Apparatus for discovering AP in a wireless communication system, characterized in that to control the access to form a channel to the AP of the highest priority in the updated map. 7. The apparatus of claim 6,
The mobile terminal requests channel state information (CSI) in a network covered by the current service providing base station based on the AP of the highest priority to the current service providing base station, and through the requested CSI. Select a channel having excellent channel gain, transmit a handoff request message to the corresponding AP through each of the selected channels, receive a response message from the corresponding AP in response thereto, and perform authentication through a specific channel among the selected channels. Apparatus for discovering AP in a wireless communication system, characterized in that the control to control. The method of claim 6, wherein the AP selection,
Search for location information close to the current location information from the previously mapped map, and if the searched location information and the current location information are included within a preset area range as a result of comparison / contrast, the AP is accessed by forming a channel from the searched location information. AP searching device in a wireless communication system, characterized in that the selection as possible AP.

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