JP2008067229A - Radio terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve hand-over with a suitable radio access point on a route without constructing a database relating to position information and authentication information of the radio access point beforehand. <P>SOLUTION: The radio terminal comprises: a radio unit 1 which performs radio communication with a radio access point; a radio access point search unit 2a which searches for a communicable radio access point; a radio access point information recognition unit 2b for recognizing radio access point information, distributed from a radio access point, containing an ID of the radio access point and its absolute position information; a moving route specification unit 2d for specifying a moving route; and a radio access point determination unit 2c for determining a radio access point to perform hand-over thereon based on the moving route and the radio access point information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless terminal that selects a wireless access point and performs wireless communication.

  Conventionally, in order to realize roaming or handover for switching a wireless access point, the wireless terminal uses the strength of reception strength on the wireless terminal side to connect with a stronger wireless access point. However, although the electric field strength of a radio wave is theoretically defined as a simple concentric circle from the wireless access point, the closest wireless access point is not always selected due to the influence of shielding or obstructions. It does not search for an efficient handover route. As described above, handover of a wireless access point based only on electric field strength may be inefficient because the number of handovers increases depending on the movement path. Therefore, it is necessary to reduce the number of complicated handovers by continuously using the same wireless access point as much as possible.

Here, for example, in Patent Document 1, an in-vehicle wireless LAN connection terminal that searches authentication information of a wireless access point in a traveling direction in a database in a vehicle and accesses the destination wireless access point using the authentication information. Is disclosed.
JP-A-2005-341254

  However, the technique disclosed in Patent Document 1 cannot be used unless the database related to the location information and authentication information of the wireless access point is constructed in advance.

  The object of the present invention is to realize efficient switching to a wireless access point without constructing a database related to the location information and authentication information of the wireless access point in advance, and to switch by this efficient switching. This is to reduce the number of times and reduce the possibility of cutting.

  According to the first aspect of the present invention, wireless means for performing wireless communication with a wireless access point, wireless access point searching means for searching for the wireless access point capable of communication, and the wireless distributed from the wireless access point Wireless access point information recognizing means for recognizing wireless access point information including at least an access point ID and position information; movement route specifying means for specifying a movement route; at least the movement route and the wireless access point information; And a wireless access point determination means for determining a wireless access point to be handed over based on the wireless terminal.

  According to the second aspect of the present invention, wireless means for performing wireless communication with a wireless access point, wireless access point searching means for searching for the wireless access point capable of communication, and the wireless distributed from the wireless access point Wireless access point information recognizing means for recognizing wireless access point information including at least an access point ID and position information, moving path specifying means for specifying a moving path, and an electric field for measuring the electric field strength of the wireless access point A hand calculated from the first distance from the point where the distance to each wireless access point is the shortest to the wireless access point on the travel route specified by the strength measuring means and the travel route specifying means, and the electric field strength. Based on the second distance from the over start point to each wireless access point Wireless access point determining means for calculating a connection sustained distance with each wireless access point and determining a wireless access point to be handed over so as to be communicable with the wireless access point having the maximum connection sustained distance A wireless terminal is provided.

  According to the present invention, it is possible to provide a wireless terminal capable of realizing efficient switching to a wireless access point, suppressing the number of times of switching by this efficient switching, and reducing the possibility of disconnection. .

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A shows a configuration example of a wireless terminal according to an embodiment of the present invention, and FIG. 1B shows a configuration example of a wireless access point with which the wireless terminal 100 can communicate. This wireless terminal can be implemented as a mobile phone, for example.

  First, as illustrated in FIG. 1A, the wireless terminal 100 includes a wireless unit 1 including an antenna 4, a route control unit 2, an electric field strength measurement unit 3, and a route management unit 4. The unit 2 further includes a wireless access point search unit 2a, a wireless access point information recognition unit 2b, a wireless access point determination unit 2c, and a movement path specifying unit 2d.

  In such a configuration, the wireless unit 1 performs wireless communication with the wireless access point 101 via the antenna 5. More specifically, the radio signal received from the antenna 4 is frequency-converted, and the converted signal is converted into a digital signal by AD conversion.

  Then, the route control unit 2 performs route control related to wireless communication with the wireless access point 101. More specifically, in the route control unit 2, the wireless access point search unit 2a searches for a communicable wireless access point 101 based on, for example, electric field strength. The wireless access point information recognition unit 2b recognizes the ID of the wireless access point 101 distributed from the wireless access point 101, and further absolute position information included in at least an IE (Information Element). The wireless access point determination unit 2c determines a suitable wireless access point 101 to be handed over according to an algorithm described in detail later. Then, the movement path specifying unit 2d specifies the movement path based on its own movement lightness information obtained by a GPS (global positioning system) function (not shown) or its own movement speed and movement direction.

  In addition, the electric field strength measuring unit 3 measures the electric field strength of the wireless access point 101. The route management unit 4 manages route information related to wireless communication of the wireless terminal 100.

  On the other hand, as illustrated in FIG. 1B, the wireless access point 101 includes a wireless unit 11, a control unit 12, and an absolute position management unit 13. The control unit 12 further includes an IE distribution unit 12a. In such a configuration, the wireless unit 11 performs wireless communication with the wireless terminal 100. The control unit 12 is responsible for overall control. In particular, the control unit 12 performs control so that an IE including at least its own ID and absolute position information is distributed by the internal IE distribution unit 12a. The absolute position management unit 13 manages absolute position information such as latitude and longitude information.

  With the above configuration, the latitude / longitude information, which is the absolute position information of the wireless access point, is inserted into the IE that is always provided wirelessly from the wireless access point 101 side, and the absolute position information of the IE on the wireless terminal 100 side, That is, based on the latitude / longitude information of the wireless access point, handover is performed with the wireless access point along the movement route of the wireless terminal 100. This realizes efficient handover.

  For specifying the movement route, the result obtained by the route search software or the train transfer software installed in the wireless terminal 100 is used, and the absolute position information and the wireless information of the wireless terminal 100 obtained from the GPS (not shown) or the like. There is a case where movement is predicted from information obtained by plotting information included in the terminal 100 for each time.

  The data used for selecting the wireless access point 101 on the route includes the moving speed and moving direction of the wireless terminal 100, the absolute position information included in the IE from the wireless access point 101, and the wireless access point obtained by the wireless terminal 100 The electric field intensity of the radio wave from 101 is used in combination. The IE can be acquired before entering the actual communicable range. These calculations are performed at any time while the wireless terminal 100 is moving.

  Hereinafter, with reference to the flowchart of FIG. 2, a handover processing procedure by the communication system according to the embodiment of the present invention will be described in detail.

  When the handover process is started, the moving path specifying unit 2d searches for the path, that is, specifies the moving path (step S1), and the radio access point searching unit 2a searches for the radio access points AP1 to APn. (Step S2).

  As for the movement route specifying by the movement route specifying unit 2d, the result obtained by the route search software or the train transfer software installed in the wireless terminal 100 as described above is used, or the GPS (global positioning not shown) is used. In some cases, movement is predicted from the absolute position information of the wireless terminal 100 obtained from the system) and the information obtained by plotting information included in the wireless terminal 100 for each time. However, it is needless to say that the present invention is not limited to these.

  The wireless terminal 100 receives the IE including the absolute position information from each of the wireless access points AP1, AP2,... APn (steps S3, S4, S5), and receives the absolute position information of the wireless access points included in the IE, That is, the wireless access point that is optimal for route prediction is selected based on the latitude and longitude information of the wireless access point (step S6).

  Then, it connects to the selected optimal wireless access point, establishes a communication session, and starts communication (steps S7 and S8). In this example, it is assumed that the wireless access point AP1 is optimal, and connection is established and communication is started.

  Thereafter, the above process is repeated as the wireless terminal 100 moves.

  That is, the wireless access point search unit 2a searches for a wireless access point (step S9) and receives an IE including absolute position information from each wireless access point AP1, AP2... APn (steps S10 and S11). ) Based on the absolute position information of the wireless access point included in this IE, the wireless access point that is optimal in route prediction is selected as needed (step S12), and the selected wireless access point that is optimal is connected, A communication session is established and communication is started (steps S13 and S14). In this example, it is assumed that the wireless access point APn is optimal, and connection is established and communication is started.

  In this way, a series of processing is completed.

  FIG. 3 conceptually illustrates and describes the relationship between the image of the person who actually holds the wireless terminal 100 moving and the wireless access points AP1 to AP5 that are arranged.

In FIG. 3, the area | region shown with the concentric circle has shown the communicable range of each radio | wireless access point AP1-AP5. The IE can be acquired before entering the region indicated by the concentric circles. In the prior art, since the access point is switched by the electric field strength received by the wireless terminal held by the person, the order of handover is simply
AP1 → AP2 → AP3 → AP4 → AP5
It becomes.

On the other hand, in the wireless terminal according to the present embodiment, in order to perform the handover while predicting the optimal handover on the movement route,
AP1 → AP3 → AP5
It becomes. Therefore, an efficient handover with a smaller number of times is realized.

  Here, the important items in determining the handover destination and reconnecting are as follows.

  • The connection must not be broken before the handover.

  • The longest connection with the switched wireless access point.

  Hereinafter, the reason why the above-described handover order is performed in the radio terminal according to this embodiment will be further described. For example, in FIG. 3, at the handover start point A calculated from the electric field strength, the distance LenY1 from the point a to the wireless access point AP1 where the distance from the moving path to the wireless access point AP1 is shortest, and the wireless from the point A From the distance LenX1 to the access point AP1, the connection continuous distance LenD1 to the wireless access point AP1 is calculated.

LenD1 = (LenX1 ² −LenY1 ² ) ^1/2
Since the connection continuous distance LenD1 corresponds to the distance from the point A to the point a, the connection with the wireless access point AP1 can be performed only twice as long as the LenD1.

  Then, when arriving at the handover start point B calculated from the electric field strength, the distance LenY2 from the point b to the wireless access point AP2 where the distance from the moving path to the wireless access point AP2 is the shortest, and the wireless access from the point B From the distance LenX2 to the point AP2, the connection continuous distance LenD2 with the wireless access point AP2 is calculated.

LenD2 = (LenX2 ² −LenY2 ² ) ^1/2
Since the connection continuous distance LenD2 corresponds to the distance from the point B to the point b, the connection with the wireless access point AP2 is possible only twice as long as the LenD2.

  Then, in either case of switching from these connection persistent distances LenD1 and LenD2 to the wireless access point AP2 and maintaining the connection with the wireless access point AP1 and then switching to the wireless access point AP3, the connection persistent distance Calculate how long will be. In this example, since the communication with the wireless access point AP3 becomes possible while traveling by a distance twice as long as the connection continuous distance LenD1 of the wireless access point AP1, the AP determination unit 2c determines that the latter is the connection continuous distance. Therefore, it is determined that the connection with the wireless access point AP1 is maintained without connecting to the wireless access point AP2, and then the connection with the wireless access point AP3 is switched.

  As described above, according to the communication system according to an embodiment of the present invention, a more appropriate wireless access point can be used at the time of wireless access point connection and wireless access point switching that are essential for wireless connection. The selection means is provided. In other words, efficient switching to a wireless access point can be realized, and this efficient switching can suppress the number of times of switching and reduce the possibility of disconnection.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and it is needless to say that various improvements and modifications can be made without departing from the spirit of the present invention.

  For example, it may be combined with train route search software and navigation software when riding on a train. Further, as a method of putting absolute position information in the wireless access point, GPS information in the mobile phone may be provided when the wireless access point is installed. In addition, when the route search information is provided to the wireless access point, it is needless to say that the wireless access points may talk independently to solve the handover and notify the wireless terminal.

(A) is a figure which shows the structural example of the radio | wireless terminal 100 which comprises the communication system which concerns on one embodiment of this invention, (b) is a figure which shows the structural example of a wireless access point. It is a flowchart explaining in detail the processing procedure of the handover by the communication system according to an embodiment of the present invention. It is a figure which shows the relationship between the image which the person who hold | maintains the radio | wireless terminal 100 actually moves, and the radio | wireless access points AP1-AP5 arrange | positioned.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Radio | wireless part, 2 ... Route control part, 2a ... AP search part, 2b ... AP information recognition part, 2c ... AP determination part, 2d ... Movement path | route identification part, 3 ... Electric field strength measurement part, 4 ... Path | route management part, DESCRIPTION OF SYMBOLS 11 ... Radio | wireless part, 12 ... Control part, 12a ... IE delivery part, 13 ... Absolute position management part.

Claims (4)

Wireless means for performing wireless communication with a wireless access point;
Wireless access point search means for searching for the wireless access point capable of communication;
Wireless access point information recognition means for recognizing wireless access point information including at least the ID and position information of the wireless access point distributed from the wireless access point;
A travel route identifying means for identifying the travel route;
Wireless access point determination means for determining a wireless access point to be handed over based on at least the moving path and the wireless access point information;
A wireless terminal comprising: The wireless access point information is included in the information element that is always distributed from the wireless access point,
The absolute position information is latitude and longitude information.
The wireless access point determination means determines a wireless access point to be handed over based on the latitude / longitude information of the wireless access point,
The wireless terminal according to claim 1, further characterized by:   2. The wireless terminal according to claim 1, wherein the moving route specifying means specifies a moving route based on a moving direction and a moving speed, and further based on absolute position information included in the wireless access point information. . Wireless means for performing wireless communication with a wireless access point;
Wireless access point search means for searching for the wireless access point capable of communication;
Wireless access point information recognition means for recognizing wireless access point information including at least the ID and position information of the wireless access point distributed from the wireless access point;
A travel route specifying means for specifying the travel route;
Electric field strength measuring means for measuring the electric field strength of the wireless access point;
On the moving path specified by the moving path specifying means, the first distance from the point where the distance to each wireless access point becomes the shortest to the wireless access point and the handover start point calculated from the electric field strength Based on the second distance to the wireless access point, the connection duration distance with each wireless access point should be calculated, and handover should be performed so that communication with the wireless access point with the maximum connection duration distance is possible. A wireless access point determining means for determining a wireless access point;
A wireless terminal comprising:

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