KR20150059952A - Terminal apparatus and method for handoff of near-range wireless access - Google Patents

Abstract

The present invention relates to a terminal apparatus and a handoff method of an NFC access. The handoff method of an NFC access comprises the steps of: scanning entire channels for a wireless access with an access point which supports a wireless LAN service; storing channel breakdown information including information of a service-viable channel among the entire channels; wirelessly accessing an access point supporting wireless LAN service through a channel among the service viable-channels; judging whether a channel state of the wirelessly accessed access point satisfies a handoff condition or not; carrying out a channel scanning for certain channels based on the channel breakdown information among the entire channels if judged as satisfying the handoff condition; and carrying out a handoff of wirelessly accessing the access point which supports the wireless LAN service through one channel among the certain channels in accordance with a result of the channel scanning for the certain channels. Therefore, since not scanning the entire channels for all bandwidths when changing a channel of an NFC access for the wireless LAN service, the present invention enables saving scanning time for an unnecessary channel, thus quickly accessing during the handoff. From an aspect of a user, since a faster access than before is allowed whenever the handoff or the handoff condition is satisfied, the present invention enables providing smooth wireless LAN communications.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hand-

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a terminal apparatus and a method for performing handoff in a short-range wireless connection for a wireless LAN service and a terminal apparatus performing the method.

Unlike a conventional Local Area Network (LAN) in which wireless local area networks (WLAN) technologies are used to connect and communicate terminal devices using a cable, a wireless local access network WiFi, which is an abbreviation of wireless fidelity, is an alias for wireless LAN, which means wireless network can be used like hi-fi audio conveniently.

According to such a wireless LAN service, a terminal device such as a smart phone, a PDA (Personal Digital Assistant), a tablet PC, or a notebook computer can use the wireless Internet within a predetermined distance around a place where an access point, which is a wireless access device, is installed.

In particular, with the popularization of mobile communication terminals and portable terminals, wireless LANs with potential as an open wireless network are rapidly expanding. Such wireless LANs are used to provide high-speed data services in schools, airports, hotels, have.

In order to provide a wireless LAN service in a mobile communication terminal, a mobile communication terminal including a wireless LAN module in addition to a mobile communication module has been developed. The wireless LAN service can be used in the wireless LAN zone. The area where the wireless Internet is available is called a hot spot or a home zone.

This wireless LAN service eliminates the need for extensive cable operations and routers resetting operations in the IT environment, such as daily movements, additions and changes, and eliminates factors limiting Internet use. It is developing as the main access method that can be done.

However, since the wireless LAN service uses the wireless data communication of the license-exempt band, a terminal device such as a mobile communication terminal exchanges with another wireless access device channel or another channel of the same wireless access device during wireless communication using the wireless Internet, There has been a problem in handoff processing.

According to the short-range wireless access handoff method of the terminal device according to the related art, when the strength of the RSSI (Received Signal Strength Indicator) becomes weak or the connection becomes unstable due to reasons such as the distance from the access point currently connected to the terminal device in the wireless LAN environment If the handoff condition is satisfied, such as when the RSSI intensity reaches a threshold value or a beacon message is not received, the terminal device transmits a handoff message to another access point of the same access point or to another access point Scan peripheral channels to turn off.

Here, after scanning the entire channel supported in the surrounding radio environment, the terminal device determines whether there is an access point satisfying a handoff condition such as whether the RSSI intensity is equal to or more than a certain standard among serviceable channels, When there are multiple access points, a handoff is made to access one of the access points according to predefined criteria.

However, in the case where the number of channels supported by the wireless environment is large at the time of handoff of the terminal apparatus, the bandwidth of all the channels is scanned unnecessarily in attempting to access the access point satisfying the hand- There is a problem that it takes a lot of time.

For example, if there are several access points in the vicinity and there are 13 channels in case of dual band supporting both 2.4 GHz and 5 GHz, and there are 19 channels in case of 5 GHz, all the channels It takes a lot of time to scan. In this manner, it takes more time than necessary to scan all the channels of each corresponding band, which is an obstacle to smooth handoff processing.

Korean Patent Publication No. 10-2009-0011484, published on February 02, 2009.

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems of the related art as described above, and it is an object of the present invention to provide a handoff method, A short-range wireless access handoff method capable of performing a handoff through one channel of a channel, and a terminal device performing the short-range wireless access handoff method.

The problems to be solved by the present invention are not limited to those mentioned above, and another problem to be solved can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a near field wireless access handoff method comprising: scanning an entire channel for wireless connection with an access point supporting a wireless LAN service; Storing channel description information including information on a serviceable channel among the entire channels; Wirelessly connecting to an access point supporting the wireless LAN service through one of the channels available for service; Determining whether a channel state of the wirelessly connected access point satisfies a handoff condition; Performing a channel scan on a part of the channels based on the channel history information if it is determined that the handoff condition is satisfied; Performing a handoff for wirelessly connecting to an access point supporting the WLAN service through one of the channels in accordance with a result of channel scanning for the partial channel.

A terminal device according to another aspect of the present invention includes: a wireless communication unit wirelessly connecting to an access point supporting a wireless LAN service through a serviceable channel among all channels; A channel scanning unit for scanning a channel for wireless connection with an access point supporting the wireless LAN service; A channel information storage unit for storing channel detail information including information on a serviceable channel among the entire channels; When a channel state of a wireless access point meets a handoff condition, the wireless LAN access point transmits a channel scan request to the wireless LAN service through one of the partial channels according to a result of channel scanning for a partial channel based on the channel history information, And a wireless connection control unit for processing a hand-off for wirelessly connecting to an access point supporting the wireless access.

According to the embodiment of the present invention, handoff is performed through one of the channels in accordance with a result of channel scanning for a part of channels based on channel history information about serviceable channels previously stored at the time of performing handoff can do.

Therefore, since all the channels of all the bands are not scanned, unnecessary channel scan time is saved, and the connection can be made faster at the time of handoff.

In addition, since the user can make a faster connection than the existing one every time the handoff condition is satisfied, it is possible to use the wireless LAN communication smoothly.

1 is a block diagram of a terminal device capable of performing a near field wireless access handoff method according to an embodiment of the present invention.
2 is a flowchart illustrating a method of a short-range wireless access handoff according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of a terminal device capable of performing a near field wireless access handoff method according to an embodiment of the present invention.

The terminal device 100 according to the embodiment includes a wireless communication unit 110, a microphone 120, a camera module unit 130, a user input unit 140, an output unit 150, a memory unit 160, An interface unit 170, a control unit 180, and the like. For example, the terminal device 100 may be implemented as a terminal device capable of communicating with a smart phone, a tablet computer, a notebook computer, a personal digital assistant (PDA), or the like.

The wireless communication unit 110 includes a mobile communication unit 111, a short range communication unit 112, a GPS (global positioning system) receiving unit 113, and the like.

The mobile communication unit 111 transmits and receives radio signals to and from at least one of a base station and an external terminal or server on a mobile communication network. Here, the wireless signal may include various types of data such as a voice call signal, a video call signal, or a text / multimedia message.

The short-range communication unit 112 transmits / receives a radio signal for short-distance communication. For example, local area communication may include Wi-Fi, Bluetooth, Radio Frequency Identification (RFID), infrared data association (IrDA), Ultra Wideband (UWB), ZigBee . For example, the short-range communication unit 112 communicates a wireless signal including a beacon message to a Wi-Fi access point and wirelessly accesses the access point through a serviceable channel among all channels for wireless LAN service.

Here, the Wi-Fi access point is disposed in the wireless LAN zone, and provides a connection function between the terminal device 100 receiving the wireless LAN service and the wired LAN, and can periodically broadcast a beacon message.

The GPS receiving unit 113 receives position information from a plurality of GPS satellites.

The microphone 120 receives an audio signal. The microphone 120 receives an external sound signal and processes it as electrical voice data in a communication mode, a recording mode, a voice recognition mode, and the like. The processed voice data can be converted into a form that can be transmitted to the mobile communication base station through the mobile communication unit 111 and output when the voice data is in the call mode.

The camera module unit 130 includes a rear camera 131 and a front camera 132. The camera module unit 130 receives a video signal under the control of the controller 180. The rear camera 131 is installed on the rear side of the terminal device 100 and the front side camera 132 is installed on the front side of the terminal device 100. Of these, the front camera 132 is mainly used for a video call and a self photographing. The rear camera 131 and the front camera 132 process image frames such as still images or moving images obtained by the image sensor in the video communication mode or the photographing mode. Then, the processed image frame can be displayed on the display unit 151. [

The user input unit 140 generates key input data that the user inputs for controlling the operation of the terminal device 100. [ The user input unit 140 includes a key pad, a dome switch, and a touch pad (static / static) capable of receiving commands or information by a user's push or touch operation. In particular, the touch pad forms a mutual layer structure with the display unit 151, which is called a touch screen. For example, the terminal device 100 may be a mobile communication terminal device including a touch screen as a kind of input / output interface.

The output unit 150 includes a display unit 151 and an audio output unit 152 and outputs various signals such as an audio signal and a video signal.

The display unit 151 displays information to be processed by the terminal device 100. For example, when the terminal device 100 is in the call mode, a UI (User Interface) or a GUI (Graphic User Interface) associated with a call is displayed. When the terminal device 100 is in the video communication mode or the photographing mode, the photographed or received images can be displayed individually or simultaneously.

In the case where the display unit 151 and the touch pad have a mutual layer structure to constitute a touch screen as described above, the display unit 151 may be an input device capable of inputting information by a user's touch in addition to the output device Can be used.

The audio output unit 152 outputs audio data received from the wireless communication unit 110 or stored in the memory unit 160 in a standby mode, a communication mode, a recording mode, a voice recognition mode, a broadcast reception mode, The sound output unit 152 outputs sound signals related to a call signal reception sound, a message reception sound, and the like, which are performed in the terminal device 100.

The memory unit 160 stores an operating system program 161 and the like and the control unit 180 executes the operating system program 161 to boot the terminal apparatus 100. [ The memory unit 160 includes a channel information storage unit 162 for storing channel history information including information on available channels in all channels according to a channel scan result by the local communication unit 112 of the wireless communication unit 110 ).

The memory unit 160 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory) , A RAM, and a ROM.

The interface unit 170 serves as an interface with all the external devices connected to the terminal device 100. Examples of the external device connected to the terminal device 100 include a card socket such as a wired / wireless headset, an external charger, a wired / wireless data port, a memory card, a SIM (Subscriber Identification Module) card, O (input / output) terminal, video I / O (input / output) terminal, and earphone.

The control unit 180 includes a channel scan unit 181, a radio access control unit 182, and the like. The control unit 180 controls the overall operation of the terminal device 100 by controlling the wireless communication unit 110, the microphone 120, the camera module unit 130, the output unit 150, the memory unit 160, do. For example, voice communication, data communication, video communication, and the like.

The channel scanning unit 181 constituting the controller 180 scans a channel of an access point capable of wirelessly connecting with the short range communication unit 112 of the wireless communication unit 110, And stores it in the channel information storage unit 162 of the memory 160.

If the handoff condition is satisfied, the radio access control unit 182 determines whether the channel state of the wireless access point satisfies the handoff condition. If the handoff condition is satisfied, And controls the short range communication unit 112 of the wireless communication unit 110 to process a handoff in which a wireless access is made to an access point supporting a wireless LAN service through one of the channels in accordance with a result of a channel scan.

In addition, the radio access control unit 182 preferentially performs a handoff according to the result of the channel scan performed on a part of the channels included in the channel detail information of the channel information storage unit 162, In case of failure, the handoff may be performed in a sub-step according to the result of the channel scan performed on the remaining channels excluding the partial channels.

In addition, the radio access control unit 182 preferentially attempts handoff according to the result of the channel scan performed on the currently used channel. If the attempted handoff fails, the radio access control unit 182 transmits a part of the channel information storage unit 162 It is possible to perform a handoff in a sub-optimal manner according to the result of channel scanning on the channel.

2 is a flowchart illustrating a method of a short-range wireless access handoff according to an embodiment of the present invention.

As described above, the short-range wireless access handoff method according to the embodiment of the present invention includes a step (S201) of scanning a whole channel for wireless connection with an access point supporting a wireless LAN service.

The method further includes storing (S203) channel history information including information on a serviceable channel among the entire channels.

(S205) wirelessly accessing an access point supporting a wireless LAN service through one channel of a serviceable channel.

The method further includes determining (S207) whether the channel state of the wirelessly connected access point meets a handoff condition.

Here, if it is determined that the handoff condition is satisfied, step (S209, S211) of performing a channel scan on a part of channels based on channel detail information among all channels is performed.

If there is an access point satisfying a handoff condition according to a result of channel scanning for a certain channel, performing a handoff for wirelessly connecting to an access point supporting the wireless LAN service through one of the channels (S213, S217).

If there is no access point satisfying the handoff condition according to the result of the channel scan for a certain channel, the access point satisfying the handoff condition is selected according to the result of the channel scan for the remaining channels excluding the partial channel. (S213, S215).

Hereinafter, a short-range wireless access handoff method and a wireless LAN service process performed by a terminal according to an embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG.

The channel scanning unit 181 of the control unit 180 configuring the terminal device 100 controls the local communication unit 112 of the wireless communication unit 110 to transmit the entire The channel is scanned (S201).

The channel scan unit 181 stores the channel detail information including the information on the serviceable channels in the channel information storage unit 162 of the memory unit 160 according to the channel scan result (S203).

The radio access control unit 182 of the control unit 180 selects any one of the channels scanned in the channel scanning unit 181 and controls the short distance communication unit 112 to wirelessly access the access point through the selected channel. Here, the radio access control unit 182 can select an optimal access point and a channel considering the RSSI strength of the scanned channels.

Then, the short-range communication unit 112 wirelessly accesses the access point through the selected channel under the control of the wireless connection control unit 182, and receives an IP address for the wireless LAN service from the wirelessly connected access point (S205).

Then, the access point periodically broadcasts a beacon message, and the short-range communication unit 112 periodically receives a beacon message from the access point.

When the short distance communication unit 112 wirelessly connects to the access point located in the wireless LAN zone, the terminal apparatus 100 can use the wireless LAN service through the wireless access point.

Meanwhile, while using the wireless LAN service, the wireless access control unit 182 determines whether the channel state of the access point wirelessly connected satisfies the handoff condition. For example, if the RSSI intensity of the currently connected channel is compared with a preset reference value and the RSSI intensity of the corresponding channel is smaller than the reference value, it is determined that the radio environment is unstable and it can be determined that the handoff condition to be handed- (S207).

If the handoff is determined by the wireless access control unit 182, the channel scanning unit 181 must select a channel for handoff again. In the prior art, Were scanned again.

However, in the present invention, the channel scan unit 181 checks channel history information previously stored in the channel information storage unit 162 of the memory unit 160 (S209), and searches all the access points Not the channel again, but re-scans the channel for some of the channels included in the stored channel history information (S211). At this time, the channel history information about the re-scanned channel may be stored in the channel information storage unit 162 so that the channel history information can be used for the subsequent channel scan.

Next, the radio access control unit 182 of the control unit 180 determines whether there is an access point satisfying the condition that the handoff condition, for example, the strength of the RSSI is equal to or higher than a certain criterion, among the channels scanned back to the channel scanning unit 181 (S213).

Here, if there is an access point satisfying the handoff condition, the radio access control unit 182 selects a corresponding channel, and performs a handoff through the selected channel by the short range communication unit 112, that is, . Here, the radio access controller 182 can select an optimal access point and a channel considering the RSSI strength of the channels scanned again.

Then, the short-range communication unit 112 performs a hand-off process for wirelessly accessing the access point through the re-selected channel under the control of the wireless connection control unit 182, and continuously uses the wireless LAN service through the wireless- (S217).

Here, in the case of a dual band supporting 2.4 GHz and 5 GHz, there are a number of access points in the periphery. In case of 2.4 GHz, there are 13 channels from 1 channel to 13 channel. In case of 5 GHz, There are 19 channels from channel 161 to channel 161. When the channel scan time required for scanning one channel is τ and the number of channels stored in step S203 is α, the connection time according to the handoff process according to the related art is τ × 32 However, according to the present invention, the connection time according to the handoff process takes a time of? X?.

For example, assuming that the channel scan time (tau) required for scanning one channel is 200 msec and that the number of channels (?) Stored in step S203 is 8, The connection time is reduced by 4.8 sec as shown in Equation 1 below.

On the other hand, if there is no access point satisfying the handoff condition among the scanned channels in step S213, partial channel scanning is performed again on the remaining channels not included in the channel detail information stored in step S203 among all the channels, The mobile station can perform a handoff to change the channel to any one of the channels. That is, the handoff is preferentially performed according to the result of the channel scan performed on the partial channels included in the channel history information of the channel information storage unit 162. If the attempted handoff fails, (S215, S217) in accordance with the result of the channel scan performed on the channel.

If the attempted handoff is unsuccessful, the handoff is attempted according to the result of the channel scan performed on the currently used channel, It is possible to perform a handoff in a sub-step according to the result of the channel scan.

For example, if a secondary channel scan is performed only on a currently used channel based on channel history information pre-stored by a primary channel scan, and if an access point suitable for wireless access exists among the secondary scanned channels, The handoff is performed. However, if there is no access point suitable for the same channel, the third channel scan is performed on the other channels based on the stored channel history information, and the third access channel is changed to an access point suitable for wireless access among the third- Lt; / RTI >

As described above, handoff can be performed through one of the channels in accordance with the result of channel scanning for a part of channels based on channel history information about serviceable channels previously stored at the time of performing handoff have.

Therefore, since all the channels of all the bands are not scanned, unnecessary channel scan time is saved, and the connection can be made faster at the time of handoff.

In addition, the user can use the wireless LAN communication smoothly since the user can make a quicker connection every time the handoff or handoff condition is satisfied.

Each block of the block diagrams attached hereto and combinations of steps of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus so that the instructions, which may be executed by a processor of a computer or other programmable data processing apparatus, And means for performing the functions described in each step are created. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory It is also possible for the instructions stored in the block diagram to produce a manufacturing item containing instruction means for performing the functions described in each block or flowchart of the block diagram. Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible that the instructions that perform the processing equipment provide the steps for executing the functions described in each block of the block diagram and at each step of the flowchart.

Also, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative embodiments, the functions mentioned in the blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

According to the embodiment of the present invention, since the entire channels of all the bands are not scanned when changing the channel of the short-range wireless connection for the wireless LAN service, unnecessary channel scan time is saved, . In addition, the user can use the wireless LAN communication smoothly since the user can make a quicker connection every time the handoff or handoff condition is satisfied.

The present invention can be applied to various terminal devices capable of communicating with a wireless LAN, such as a smart phone, a tablet computer, a notebook computer, a PDA, etc., which can communicate with a wireless LAN using a short distance communication such as a WiFi.

100: terminal device 110: wireless communication part
112: Local area communication unit 120: Microphone
130: camera module section 140: user input section
150: output unit 160: memory unit
161: Operating system program 162: Channel information storage unit
170: interface unit 180: control unit
181: Channel scanning unit 182: Wireless connection control unit

Claims (6)

Scanning an entire channel for wireless connection with an access point supporting a wireless LAN service;
Storing channel description information including information on a serviceable channel among the entire channels;
Wirelessly connecting to an access point supporting the wireless LAN service through one of the channels available for service;
Determining whether a channel state of the wirelessly connected access point satisfies a handoff condition;
Performing a channel scan on a part of the channels based on the channel history information if it is determined that the handoff condition is satisfied;
Performing a handoff for wirelessly connecting to an access point supporting the wireless LAN service through one of the channels in accordance with a result of channel scanning for the selected channel
The method comprising the steps of: The method according to claim 1,
A handoff is attempted according to a result of a channel scan performed on the partial channels included in the channel history information, and when the attempted handoff is unsuccessful, Try to hand-off in a sub-scan according to the result of channel scan
The method comprising the steps of: The method according to claim 1,
The handoff is attempted according to the result of the channel scan performed on the currently used channel, and if the attempted handoff is unsuccessful, the handoff is performed in accordance with the result of the channel scan on the partial channel. To try
The method comprising the steps of: A wireless communication unit wirelessly connecting to an access point supporting a wireless LAN service through a serviceable channel among all channels;
A channel scanning unit for scanning a channel for wireless connection with an access point supporting the wireless LAN service;
A channel information storage unit for storing channel description information including information on a serviceable channel among all the channels;
When a channel state of a wireless access point meets a handoff condition, the wireless LAN access point transmits a channel scan request to the wireless LAN service through one of the partial channels according to a result of channel scanning for a partial channel based on the channel history information, A radio access control unit
. 5. The method of claim 4,
A handoff is attempted according to a result of a channel scan performed on the partial channels included in the channel history information, and when the attempted handoff is unsuccessful, Try to hand-off in a sub-scan according to the result of channel scan
. 5. The method of claim 4,
The handoff is attempted according to the result of the channel scan performed on the currently used channel, and if the attempted handoff is unsuccessful, the handoff is performed in accordance with the result of the channel scan on the partial channel. To try
.

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