JP2009212769A - Wireless terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change setting of a threshold in handover by a wireless terminal. <P>SOLUTION: The wireless terminal 1 which compares received radiowave intensity which is the intensity of the received radiowave with a threshold 121 stored in a storage part 12, and starts the handover when the received radiowave intensity is a value equal to or less than the threshold 121 as a result of comparison, is characterized by including: a measurement part 13 which measures the received radiowave intensity received by an antenna 15 when a threshold determination instruction is input from an input part 16; and a threshold determination processing part 112 which stores the measured received radiowave intensity in the storage part 12 as the threshold 121 for determining whether or not the handover is started. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless terminal.

In a wireless local area network (LAN), a wireless terminal selects an access point determined to have the most stable communication from among a plurality of access points, and performs wireless communication with the selected access point for communication.
If the wireless terminal determines that stable communication is not possible with the access point connected so far due to movement of the wireless terminal, the wireless terminal searches for another access point. If an access point that can perform stable communication is found as a result of the search, the connection with the access point that has been connected so far is disconnected and the connection with the newly found access point is performed. Switching the access point to be connected according to the communication status in this way is called handover.
With respect to such a handover, a mobile device is disclosed that uses the predicted radio wave intensity to advance the completion time of the handover process (see, for example, Patent Document 1).

8 to 10 are diagrams showing an outline of a conventional handover.
FIG. 8 is a diagram showing an outline of handover, (a) is a diagram showing the relationship between a wireless terminal and each access point, and (b) is a graph showing the distance from the access point and the received radio wave intensity. It is a graph which shows a relationship.
As shown in FIG. 8A, it is assumed that the wireless terminal 1 ′ has moved from the access point A 200 to the access point B 201. At this time, FIG. 8B is a graph in which the horizontal axis represents the distance from the access point A 200 and the vertical axis represents the radio wave intensity (reception radio wave intensity) received by the radio terminal 1 ′.
As shown in FIG. 8B, when the radio terminal 1 ′ moves away from the access point A 200, the received radio wave intensity at the radio terminal 1 ′ decreases in a curve. Therefore, a threshold is set in advance, and when the received radio wave intensity falls below this threshold, the wireless terminal 1 ′ switches the connection from the access point A 200 to the access point B 200. As described above, the radio terminal 1 ′ compares and determines the received radio wave intensity from the access point received by the radio terminal 1 ′ and the threshold value of the received radio wave intensity preset in the radio terminal 1 ′. Is done.

A circle 301 in FIG. 8A indicates a boundary where the received radio wave intensity from the access point A 200 in the wireless terminal 1 ′ reaches the set threshold when the threshold is set as shown in FIG. 8B. . That is, if it is within the area of the circle 301, the wireless terminal 1 ′ can establish communication connection with the access point A 200.
Similarly, a circle 302 indicates a boundary where the received radio wave intensity from the access point B 201 in the wireless terminal 1 ′ reaches the set threshold when the threshold is set as shown in FIG. 8B. That is, if it is within the area of the circle 302, the wireless terminal 1 ′ can establish communication connection with the access point B 201.

As shown in FIG. 8A, even if the wireless terminal 1 ′ moving in the direction from the access point A 200 to the access point B 201 starts handover at a point 303 on the circle 301, the point 303 Wireless terminal 1 ′ can switch communication connection from access point A 200 to access point B 201.
JP 2006-295410 A

However, depending on the transmission output of the access point and the positional relationship between the access points, the threshold value preset in the wireless terminal 1 ′ may not be suitable for handover.
FIG. 9 is a diagram for explaining handover when the threshold values are the same as those in FIG. 8 and access points are separated from each other, and (a) is a diagram showing the relationship between a wireless terminal and each access point. (B) is a graph which shows the relationship between the distance from an access point, and received radio wave intensity.
In FIG. 9, elements similar to those in FIG. 8 are denoted by the same reference numerals and description thereof is omitted.
A circle 304 is the same as the circle 301 in FIG. 8A, and a circle 305 is the same as the circle 302 in FIG.
As shown in FIG. 9A, the wireless terminal 1 ′ moving from the access point A 200 to the access point B 201 reaches a point 306 on the circle 304 (the received radio wave intensity from the access point A 200 reaches a threshold value). Even if the handover is started at point (point), since the point 306 is outside the area of the circle 305, the wireless terminal 1 ′ cannot switch the communication connection from the access point A 200 to the access point B 201.
As described above, when the boundary between the access points does not overlap, even if the received radio wave intensity at the wireless terminal 1 ′ is lower than the threshold, the wireless terminal 1 ′ is sufficient as shown in FIG. An access point that can receive radio waves of radio field strength cannot be found and a handover cannot be performed.

FIG. 10 is a diagram for explaining handover when the distance between access points is the same as in FIG. 9 and the threshold value is lowered, and (a) is a diagram showing the relationship between the wireless terminal and each access point. (B) is a graph which shows the relationship between the distance from an access point, and received radio wave intensity.
10, elements similar to those in FIGS. 8 and 9 are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 10, when the threshold value is lowered, the area where the wireless terminal 1 ′ can connect communication with the access point A 200 increases from the inside of the circle 304 to the inside of the circle 307. Similarly, the area where communication can be connected to the access point B 201 extends from the inside of the circle 305 to the inside of the circle 308. Therefore, when the wireless terminal 1 ′ moves from the access point A 200 toward the access point B 201, the position where the handover is started can be extended from the point 306 to the point 309. Since the point 309 is within the area of the circle 308, the wireless terminal 1 ′ can switch the communication connection to the access point B 201.
In this way, the handover start position can be extended by lowering the threshold value set in the wireless terminal 1 ′.

  However, even in the technique of lowering the set threshold value and extending the start position of the handover as shown in FIG. 10, in order to set an appropriate threshold value, the radio wave intensity received from the access point is wireless. It is necessary to measure with a measuring device other than the terminal. For this reason, when a user wants to change a threshold value, it is necessary to prepare a measuring instrument etc., and there exists a problem that a threshold value cannot be changed easily.

  An object of the present invention is to change the setting of a threshold value in handover at a wireless terminal.

  In order to solve the above-described problem, the present invention provides a wireless terminal that performs handover using communication information related to a radio wave communication state and a threshold value, and when the threshold value determination instruction is input from an input unit, An acquisition unit that acquires information, and a threshold value determination processing unit that generates a threshold value for determining whether to start handover based on the acquired communication information, and stores the generated threshold value in a storage unit. And

  According to the present invention, it is possible to change the setting of the threshold value in handover at the wireless terminal.

  Embodiments of a wireless terminal according to the present invention will be described below with reference to the drawings.

(First embodiment: configuration)
FIG. 1 is a diagram illustrating a configuration example of a wireless terminal according to the first embodiment.
The wireless terminal 1 includes a processing unit 11, a storage unit 12, a measurement unit 13 (acquisition unit), a transmission / reception unit 14, an antenna 15, and an input unit 16.

The processing unit 11 generates and determines a threshold value 121 based on the information acquired from the input unit 16 and the received radio wave intensity acquired from the measurement unit 13 by being set in the MENU, for example, and the determined threshold value 121 is set. It has a function of storing in the storage unit 12 or performing a handover using the determined threshold value 121. The detailed configuration of the processing unit 11 will be described later. The storage unit 12 stores a threshold value 121 determined by the processing unit 11.
The measurement unit 13 has a function of measuring the received radio wave intensity (communication information) of the radio wave received by the transmission / reception unit 14. The transmission / reception unit 14 has a function of transmitting / receiving information via the antenna 15.

The processing unit 11 includes a handover control unit 113, a threshold value determination processing unit 112, and an input processing unit 111.
The input processing unit 111 has a function of starting threshold determination processing based on information input via the input unit 16. The threshold value determination processing unit 112 has a function of storing the received radio wave intensity acquired from the measurement unit 13 in the storage unit 12 as a new threshold value 121. The handover control unit 113 has a function of performing a handover using the threshold 121 stored in the storage unit 12. The wireless terminal 1 may be a wireless local area network (LAN) terminal or a mobile phone.

  Next, the threshold setting process according to the present embodiment will be described along FIGS. 2 to 4 with reference to FIG. Each process shown in FIGS. 2 to 4 is executed in parallel.

(Input processing)
FIG. 2 is a flowchart showing the flow of input processing according to the first embodiment.
The input processing unit 111 monitors whether there is a threshold determination start input from the input unit 16 by determining whether there is a threshold determination start input from the input unit 16 (S101).
As a result of step S101, when there is no threshold determination start input (S101 → No), the input processing unit 111 returns the process to step S101.
As a result of step S101, when there is a threshold determination start input (S101 → Yes), the input processing unit 111 notifies the threshold determination processing unit 112 that the threshold determination start mode is ON (S102).
Then, the input processing unit 111 determines whether or not there is a threshold value determination instruction input from the input unit 16 with the current received radio wave intensity as the threshold value 121 (S103). Monitor for presence.
As a result of step S103, when there is a threshold determination instruction input (S103 → Yes), the input processing unit 111 notifies the threshold determination processing unit 112 that the threshold determination instruction is ON (S104).

As a result of step S103, when there is no threshold determination instruction input (S103 → No), the input processing unit 111 notifies the threshold determination processing unit 112 that the threshold determination instruction is OFF (S105).
Next, in step S105, the input processing unit 111 determines whether there is a threshold value determination start input from the input unit 16 (S106).
As a result of step S106, when there is a threshold determination start input (S106 → Yes), since the threshold determination is still in the standby state, the input processing unit 111 returns the process to step S103.
As a result of step S106, when there is no threshold determination start input (S106 → No), the input processing unit 111 notifies the threshold determination processing unit 112 that the threshold determination start mode is OFF (S107). That is, the input processing unit 111 cancels the standby state for threshold determination and notifies the threshold determination processing unit 112 to that effect. Thereafter, the input processing unit 111 returns the process to step S101.

(Threshold determination process)
FIG. 3 is a flowchart showing a flow of threshold determination processing according to the first embodiment.
The threshold determination processing unit 112 determines whether the threshold determination start mode is ON by determining whether the threshold determination start mode ON notification is received from the input processing unit 111 or whether the threshold determination start mode OFF notification is received. Is determined (S201).
If the threshold determination start mode is not ON as a result of step S201 (S201 → No), the threshold determination processing unit 112 proceeds to step S201 because the threshold determination start is not instructed from the input unit 16. To return.
If the threshold determination start mode is ON as a result of step S201 (S201 → Yes), the threshold determination processing unit 112 notifies the handover control unit 113 that the threshold determination mode is ON (S202).
Then, the threshold determination processing unit 112 determines whether the threshold determination instruction ON is received from the input processing unit 111 or whether the threshold determination instruction OFF is received from the input processing unit 111, so that the threshold determination instruction is ON. It is determined whether or not there is (S203).
As a result of step S203, when the threshold value determination instruction is ON (S203 → Yes), the threshold value determination processing unit 112 acquires the current received radio wave intensity from the measurement unit 13 (S204), and uses the acquired received radio wave intensity as a new value. The threshold value 121 is determined, and the determined threshold value 121 is written in the storage unit 12 (S205). Then, the threshold determination processing unit 112 notifies the handover control unit 113 that the threshold determination mode is OFF (S206), and returns the process to step S201. The received radio wave intensity acquired in step S204 may be the received radio wave intensity having the largest value among the received radio waves when receiving radio waves from a plurality of access points, or received so far. The received radio wave intensity from the access point that has been used may be acquired.

As a result of step S203, when the threshold determination instruction is not ON (S203 → No), the threshold determination processing unit 112 receives a notification of threshold determination start mode ON from the input processing unit 111 or a notification of threshold determination start mode OFF. It is determined whether or not the threshold determination start mode is ON in the step S203 (S207).
When the threshold value determination start mode is ON (S207 → Yes), the threshold value determination is on standby, but since it is not actually allowed to set the current received radio wave intensity as the threshold value 121, the threshold value determination processing unit 112 The process returns to step S203.
When the threshold value determination start mode is not ON (S207 → No), the threshold value determination processing unit 112 advances the process to step S206 because the standby state for threshold value determination is cancelled.

(Handover control)
FIG. 4 is a flowchart showing a flow of handover control according to the first embodiment.
First, the handover control unit 113 determines whether the threshold determination mode is ON by determining whether the input determination mode ON notification is received from the threshold determination processing unit 112 or whether the input determination mode OFF notification is received. Is determined (S301).
If the threshold value determination mode is ON as a result of step S301 (S301 → Yes), the threshold value 121 is being set, so the handover controller 113 returns the process to step S301 without performing the handover.
If the threshold value determination mode is not ON as a result of step S301 (S301 → No), the handover control unit 113 acquires the received radio wave intensity from the measurement unit 13 (S302), and acquires the threshold value 121 from the storage unit 12. (S303).
Then, the handover control unit 113 determines whether or not the handover start condition is satisfied by determining whether or not the acquired received radio wave intensity indicates a value equal to or less than the threshold 121 (S304).

As a result of step S304, when the handover start condition is not satisfied (S304 → No), the handover control unit 113 returns the process to step S301.
As a result of step S304, when the handover start condition is satisfied (S304 → Yes), the handover control unit 113 executes the handover (S305), and returns the process to step S301 when the handover is completed.

(Effect of 1st Embodiment)
According to the first embodiment, the threshold value 121 can be the position at which the user of the wireless terminal 1 wants to execute a handover or the received radio wave intensity received at the time of the radio wave intensity at which the threshold value 121 is desired. That is, for example, when the access points are separated as shown in FIG. 10A, it is assumed that the wireless terminal 1 ′ is moving from the access point A 200 toward the access point B 201. The movement of the wireless terminal 1 ′ occurs, for example, when the user moves while holding the wireless LAN terminal, uses a mobile phone in a passenger seat of a car, or uses a mobile phone in a train. It is assumed that the threshold of the wireless terminal 1 ′ is set so that the handover is started at the position of the point 306. In this state, it is assumed that the user uses the wireless terminal 1 ′ at the position of the point 309. At this time, the wireless terminal 1 ′ searches for an access point that can be connected. However, since the received radio wave intensity from the closest access point B 201 is also equal to or less than the threshold value, the wireless terminal 1 ′ cannot be handed over. Therefore, the wireless terminal 1 ′ has a function of performing threshold setting processing according to the first embodiment, and changes the received radio wave intensity at the point 309 to a threshold, for example. In this case, the start position of the handover extends to the circle 307, and the radio terminal 1 ′ can connect communication with the access point B 201 by performing the handover.

Further, in the threshold setting process according to the first embodiment, when the wireless terminal 1 ′ uses the strongest received radio wave intensity among the received radio waves as a threshold, the threshold setting process according to the first embodiment is performed at point 309. Then, the start position of the handover is a circle passing through the point 309 with the access point B 201 as the center. Even in this case, the radio terminal 1 ′ can perform handover and connect communication with the access point B 201.
That is, the user can set the threshold value 121 suitable for the handover only by the wireless terminal 1.

(Second Embodiment: Configuration)
FIG. 5 is a diagram illustrating a configuration example of a wireless terminal according to the second embodiment.
In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.
The wireless terminal 1a in FIG. 5 is different from the wireless terminal 1 in FIG. 1 in that the received radio wave intensity history 122 in which the received radio wave intensity in the past is stored as a history is stored in the storage unit 12a, and the processing unit 11a. The threshold determination processing unit 112a in FIG. 2 acquires the received radio wave intensity in the past fixed period from the received radio wave intensity history 122 of the storage unit 12a, and the received radio wave intensity in the past fixed period and the current received radio wave intensity acquired from the measuring unit 13 This has a function of generating and determining a new threshold value 121 based on the above.

(Threshold determination process)
FIG. 6 is a flowchart showing a flow of threshold determination processing according to the second embodiment.
In FIG. 6, the same steps as those in FIG. 3 are denoted by the same step numbers and description thereof is omitted.
After determining that the threshold value determination instruction is ON in step S203 (S203 → Yes), the threshold value determination processing unit 112a acquires the received radio wave intensity in the past certain period from the received radio wave intensity history 122 from the storage unit 12a (S401). ).
Then, the threshold determination processing unit 112a acquires the current received radio wave intensity from the measurement unit 13 in step S204, and then acquires the received radio wave intensity history 122 for the past certain period acquired in step S401 and the measurement unit 13 in step S204. Based on the current received radio wave intensity, a new threshold 121 is generated (S402). For example, the threshold value determination processing unit 112a calculates an average value of the received radio wave intensity history 122 in the past certain period and the current received radio wave intensity, and sets the calculated average value as the new threshold value 121. Then, the threshold value determination processing unit 112a writes the threshold value 121 generated in step S402 in the storage unit 12a (S205).

(Effect of 2nd Embodiment)
According to the second embodiment, not only the received radio wave intensity received at the present time but also the received radio wave intensity measured in the past is used for generation and determination of the threshold value 121. As a result, rather than determining the threshold 121 from the received radio wave intensity received from one access point, the threshold 121 is determined using the received radio wave intensity values received at a plurality of locations in the past. Can be set.

In the first embodiment and the second embodiment, the received radio wave intensity is used to determine the threshold value 121. However, the present invention is not limited to this. For example, the threshold value 121 can be determined. For example, the packet transmission / reception error increases as the number of re-transmission / reception increases as the communication status deteriorates. In this case, the handover control unit 113 executes handover when the number of packet retransmissions and the error occurrence rate are equal to or greater than the threshold value 121.
Further, handover may be performed by combining at least two of the received radio wave intensity, the number of packet retransmissions, and the error occurrence rate. That is, threshold values 121 relating to at least two of the received radio wave intensity, the number of packet retransmissions, and the error occurrence rate are respectively generated and stored in the storage unit 12a. In step S304 of FIG. It may be determined whether or not the start condition is satisfied.

(Hardware configuration)
FIG. 7 is a diagram illustrating an example of the hardware configuration of the wireless terminal according to the present embodiment.
The wireless terminals 1, 1 a include a CPU (Central Processing Unit) 401, a RAM (Random Access Memory) 402, a ROM (Read Only Memory) 403, a wireless transmission / reception device 404 that transmits radio to the antenna 15, and the like. The CPU 401, RAM 402, ROM 403, and wireless transmission / reception device 404 are connected to each other via a bus 405.
The processing unit 11, the input processing unit 111, the threshold value determination processing units 112 and 112 a, the handover control unit 113, and the measurement unit 13 in FIGS. 1 and 5 are developed by the program stored in the ROM 403 in the RAM 402 and executed by the CPU 401. It is embodied by.
The wireless transmission / reception device 404 corresponds to the transmission / reception unit 14 of FIGS. 1 and 5 and includes an oscillator, a modulator, an amplifier, and the like.
The storage units 12 and 12a in FIGS. 1 and 5 correspond to the ROM 403, but are not limited thereto, and the threshold 121 and the received radio wave intensity history 122 may be stored in an external storage device or the like.

It is a figure which shows the structural example of the radio | wireless terminal which concerns on 1st Embodiment. It is a flowchart which shows the flow of the input process which concerns on 1st Embodiment. It is a flowchart which shows the flow of the threshold value determination process which concerns on 1st Embodiment. It is a flowchart which shows the flow of the handover control which concerns on 1st Embodiment. It is a figure which shows the structural example of the radio | wireless terminal which concerns on 2nd Embodiment. It is a flowchart which shows the flow of the threshold value determination process which concerns on 2nd Embodiment. It is a figure which shows the example of the hardware constitutions of the radio | wireless terminal which concerns on this embodiment. It is a figure which shows the outline of the outline of a hand-over, (a) is a figure which shows the relationship between a radio | wireless terminal and each access point, (b) shows the relationship between the distance from an access point, and received radio wave strength. It is a graph to show. The threshold value is the same as in FIG. 8, and is a diagram for explaining handover when access points are separated from each other, (a) is a diagram showing the relationship between a wireless terminal and each access point, (b) These are graphs showing the relationship between the distance from the access point and the received radio wave intensity. The distance between access points is the same as in FIG. 9, and is a diagram for explaining handover when the threshold is lowered, (a) is a diagram showing the relationship between a wireless terminal and each access point, (b) These are graphs showing the relationship between the distance from the access point and the received radio wave intensity.

Explanation of symbols

1, 1a, 1 'Wireless terminal 11, 11a Processing unit 12, 12a Storage unit 13 Measuring unit 14 Transmission / reception unit 15 Antenna 16 Input unit 111 Input processing unit 112, 112a Threshold determination processing unit 113 Handover control unit 121 Threshold 122 Received radio wave intensity History 401 CPU
402 RAM
403 ROM
404 wireless transceiver 405 bus

Claims (6)

A wireless terminal that performs handover using communication information related to a radio wave communication state and a threshold,
When a threshold determination instruction is input from the input unit, an acquisition unit that acquires the communication information;
A wireless terminal comprising: a threshold value determination processing unit that generates a threshold value for determining whether or not to start handover based on the acquired communication information, and stores the generated threshold value in a storage unit. The storage unit stores past communication information that is the communication information acquired in the past,
The threshold value determination processing unit generates the threshold value based on communication information at the time of input, which is communication information acquired at the time of the input, and the past communication information. Wireless terminal.   The wireless terminal according to claim 1, wherein the communication information is radio wave reception intensity.   The wireless terminal according to claim 1, wherein the communication information is a number of packet retransmissions.   The wireless terminal according to claim 1, wherein the communication information is a packet error occurrence rate. The communication information is at least two of radio wave reception intensity, packet retransmission count, and packet error rate,
The threshold determination processing unit generates a threshold for at least two of the number of packet retransmissions and a packet error rate at the time of acquisition, and stores the generated threshold in the storage unit. The wireless terminal according to claim 1 or 2.

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