JP4268148B2 - Mobile device and mobile device communication method - Google Patents

Description

The present invention relates to a mobile device and a mobile device communication method .

  Mobile devices such as mobile phones and mobile wireless terminals perform wireless communication via access points in a communication network such as a wireless LAN configured by a plurality of access points (APs) serving as base stations. The mobile device performs wireless communication with the access point to which the mobile device belongs, and a predetermined channel (Ch: Channel) and profile (protocol characterized for each product group) defined for each access point. .

When the mobile device moves between access points, the mobile device performs handover (Hand Over) to switch the access point from the access point that has belonged so far to an access point that has a better communication state at a shorter distance. At this time, the mobile device performs a scan (Scan) as to which channel and profile enable communication, searches for an access point with the best communication state, and belongs to that access point (Patent Document 1). reference).
JP 2004-235963 A

  However, the above mobile device has a drawback that it takes time to scan a base station with the best communication state at the time of handover. For this reason, the standby time (communication interruption time) and continuous call time at the time of handover of the mobile device are greatly affected. In addition, there is a problem that power consumption during scanning is large.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mobile device and a mobile device communication method capable of performing scanning in a short time and with low power consumption during handover.

The present invention is a mobile device that performs wireless communication via a base station in a communication network composed of a plurality of base stations, and includes a radio field strength determination mechanism that determines a radio field strength for each channel from the base station, Whether or not communication is possible using a profile stored in the storage mechanism for only a channel that has been determined to have a radio field strength equal to or greater than a threshold by the radio field strength determination mechanism at the time of handover. includes a scan performing unit for performing a scan, the storage mechanism, priority storing a profile of the profile and the lower-level, the scan execution unit, for determining channels to a threshold or more radio wave intensity, the radio wave strength determined in the order signal strength is determined high by a mechanism, first scans the upper profile, scan until communicable Continue with, when possible communication by any of the determined channel to a threshold or more radio wave intensity communicates with the channel and the upper profile, by the upper profile by all channels is determined that the threshold value or more radio wave intensity when the communication is not possible, the determination channel to a threshold or more radio field intensity, in the order the field intensity is high, which is determined by a radio wave intensity determination mechanism to scan by the lower profile, continue to scan until the communicable When communication is possible through any of the channels determined to have a radio field intensity equal to or higher than the threshold, communication is performed with the channel and a lower profile . Further, the present invention is a communication method for a mobile device that performs wireless communication via a base station in a communication network composed of a plurality of base stations, the step of determining the radio field intensity for each channel from the base station; , Storing a profile for performing wireless communication with the base station and only a channel determined to have a radio field intensity equal to or higher than a threshold value by a step for determining the radio field intensity at the time of handover by the profile stored by the step of storing the profile A step of scanning whether or not communication is possible, and in the step of storing the profile, a higher priority profile and a lower profile are stored, and in the step of scanning whether or not communication is possible, a threshold value is stored. for more wave intensity and the determined channel, determine by determining received signal strength In order the field intensity is high, which is to scan the first upper profile, continue to scan until communication becomes possible, and the channel whenever possible communication by any of the determined channel to a threshold or more radio wave intensity higher communicate via a profile, when not communicate by the upper profile by all channels is determined that the threshold value or more radio field intensity, the determination channel to a threshold or more radio wave intensity, line physician scanning by the lower profile This is a communication method for a mobile device that continues scanning until communication is possible, and when communication is possible through any of the channels determined to have a radio field intensity equal to or higher than the threshold, communication is performed with the channel and a lower profile .

According to this configuration, the radio wave intensity determining mechanism or the step of determining the radio wave intensity determines the radio wave intensity for each channel, so that a channel having high communication connectivity can be predicted in advance at the time of handover. In addition, the step of performing a scan as to whether the scan execution unit or the communication is possible is performed by performing a scan as to whether the communication can be performed according to a predetermined profile only for a channel determined to have a radio field intensity equal to or higher than a threshold by the radio field intensity determination mechanism. New attribution can be selected with a small number of scans. Therefore, scanning can be completed in a short time and with low power consumption at the time of handover. Further, the step of storing the storage mechanism or profile stores the profile having the higher priority and the lower profile, and the step of scanning whether or not the scan execution unit or communication is possible determines that the radio wave intensity is greater than or equal to the threshold value. In the order of the highest signal strength determined by the signal strength determination mechanism, the first channel is scanned with the higher profile, and the scan is continued until communication is possible. when communicable communicates with the channel and the upper profile depending, when not communicate with the upper profile by all channels is determined that the threshold value or more radio field intensity was determined to be the threshold value or more radio wave intensity for channel, signal strength is determined by a radio wave intensity determination mechanism In descending order, to scan by the lower profile, continue to scan until communication becomes possible, performs communication by the channel and the lower profile when communicable by any of the determined channel to a threshold or more radio wave intensity Therefore, there is a high possibility that communication can be performed using a higher priority profile.

According to the mobile device and the mobile device communication method of the present invention, scanning can be completed in a short time and with low power consumption during handover.

  Hereinafter, a mobile device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the mobile device according to the first embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a configuration of a mobile device according to the first embodiment of the present invention. The mobile device 10 according to the present embodiment includes a radio wave intensity determination mechanism 12, a storage mechanism 14, a scan execution unit 16, and a control unit 18.

  The radio wave intensity determination mechanism 12 is physically composed of an antenna receiver, an RF circuit, a signal converter, a comparator, and the like. The radio wave intensity determination mechanism 12 receives a radio wave signal from the access point, and for each channel from the access point. Determine the radio field strength. The radio wave intensity determination mechanism 12 of this embodiment receives radio waves of a channel to which it belongs, and also receives radio waves of channels other than the channel to which it currently belongs, and monitors the radio wave intensity of that channel.

  The storage mechanism 14 is physically composed of a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and stores a profile for performing wireless communication with an access point. This profile includes a group name for identifying a wireless LAN network such as an ESSID (Extended Service Set IDentifier), a provider that provides a communication network, and the like. These profiles are stored in the storage mechanism 14 with a predetermined priority according to user settings or the like. The storage mechanism 14 stores the radio field intensity of each channel determined by the radio field intensity determination mechanism 12.

  The scan execution unit 16 is physically composed of an antenna transmission unit, an RF circuit, a signal converter, a comparator, and the like. The scan execution unit 16 stores only a channel determined to have a radio field intensity equal to or higher than a threshold by the radio field intensity determination mechanism 12. 14 is scanned according to the profile stored in 14.

  The control unit 18 is physically composed of a CPU (Central Processing Unit), ROM, RAM, and the like, and controls operations of the radio wave intensity determination mechanism 12, the storage mechanism 14, and the scan execution unit 16.

  FIG. 2 is a table showing the relationship between the channel priority and the radio wave intensity for each channel according to the first embodiment of the present invention. In the present embodiment, such information is stored in the storage mechanism 14 together with the predetermined profile described above. FIG. 2 shows an example in which radio waves related to channels Ch1, Ch6, Ch11, and Ch14 are received from access points around the mobile device. The radio field intensity for each channel is determined by the radio field intensity determination mechanism 12 and stored in the storage mechanism 14 via the control unit 18. Channels are prioritized in order of radio field strength. Information regarding the radio field intensity of the channel is sequentially updated to the latest information from the radio field intensity determination mechanism 12. It should be noted that information regarding channels for which no new radio waves are received from outside for a certain period of time is automatically updated. At the time of this automatic update, the priority of the channel to be automatically updated is the fourth (lowest) in FIG. Leave the field of field strength blank. The channel that was the fourth (lowest) until then is moved up to the third (first higher than the lowest). This can prevent scanning with old information. It is determined whether the radio field intensity for each channel is equal to or greater than a predetermined threshold value, and the result is stored in the storage mechanism 14.

  Hereinafter, the operation of the mobile device according to the present embodiment will be described. FIG. 3 is a diagram illustrating an example of handover of a mobile device in the first embodiment of the present invention. In this example, the mobile device 10 is moving between the access points 20, 22, 24 and 26 in the direction of the arrow in the figure. The channel and profile of each access point are as shown in the figure. In this example, the mobile station 10 leaves the access point 20 belonging to Ch1, profile P (1), and Ch14, profile P (1 ) Belonging to the access point 26.

  Here, the operation at the time of handover of a conventional mobile device will be described first. FIG. 4 is a table showing the order of scanning in the conventional mobile device, and FIG. 7 is a flowchart showing handover in the conventional mobile device. As shown in FIG. 4, the priority order of the three profiles is the order of profiles P (1), P (2), and P (3) from the top. The radio field intensity of each channel is as shown in the table of FIG.

  In this case, as shown in FIG. 7, when communication is being performed with a certain Ch (S10), the search for the next communication destination is started because the radio wave intensity falls below the threshold (S12). In this case, the initial value is set to n = 1 (S14), and all channels are scanned with the profile P (n) of the priority order n (S16). That is, as shown in FIG. 4, first, all the channels Ch1, Ch6, Ch11, and Ch14 are scanned by the profile P (1). It is determined whether or not communication is possible on any channel (S18). If communication is possible, communication is performed with the channel and a profile (S20). If communication is not possible, the profile P (n) with a lower priority of n = n + 1, that is, sequentially with profiles P (2) and P (3) as shown in FIG. All channels Ch1, Ch6, Ch11, and Ch14 are scanned (S22). Then, scanning is continued until communication is possible with any channel and profile (S18, S22).

Consider the case where the scan current of the mobile device is 1 A and the scan time for each channel is 1 s. In this case, in the conventional mobile device, the total current consumption is as follows.
Maximum total current consumption = 4Ch x 1s x 1A x 3 profiles
= 12As
Minimum total current consumption = 4Ch x 1s x 1A x 1 profile
= 4As

  In other words, since all the channels are scanned in the conventional mobile device, even if communication can be performed with the profile with the highest priority for scanning first, all the channels (see FIGS. 4 and 7) In the example, the current consumption for performing the scan of 4 channels) is required to the minimum. Furthermore, it takes time to scan all channels.

  FIG. 5 is a table showing the order of scanning according to the first embodiment of the present invention, and FIG. 8 is a flowchart showing handover in the first embodiment of the present invention. As shown in FIG. 5, in the present embodiment, only a channel having a radio field intensity equal to or higher than a threshold is scanned. In the example of FIG. 5, the threshold value is set to −50 dB, and only Ch11 (−50 dB) and Ch14 (−40 dB), which are channels with higher radio field strength, are scanned. The priorities of the three profiles are the same as in the example of the conventional mobile device shown in FIG.

  In this embodiment, as shown in FIG. 8, when communication is being performed with a certain Ch, radio waves of other channels are also received (S110). The radio wave intensity determination mechanism 12 determines the radio wave intensity for each channel, and extracts channels that are equal to or higher than the threshold as Ch (1) to Ch (m) in the order of the radio wave intensity (S112). In the example of FIG. 5, Ch (1): Ch14 (−40 dB) and Ch (2): Ch11 (−50 dB), which are radio wave strengths equal to or higher than the threshold −50 dB, are extracted.

The initial values are set to m = 1 (S114) and n = 1 (S116). Based on the profile P (n) with the priority order n stored in the storage mechanism 14, the Ch (m) with the field strength order m is scanned (S118). That is, as shown in FIG. 5, first, the channel Ch (1): Ch14 is scanned first by the profile P (1). It is determined whether or not communication is possible (S120). If communication is possible, communication is performed with the channel and a profile (S122). If communication is impossible, the profile P (n) having a lower priority of priority n = n + 1, that is, as shown in FIG. 5, sequentially by profiles P (2) and P (3), Channel Ch (1): Ch14 is scanned (S126). When n = n _max is reached, that is, after the channel is scanned by all profiles (S124), the channel Ch (m) having a lower radio wave intensity rank of the radio wave intensity rank m = m + 1, that is, as shown in FIG. As described above, in the channel Ch (2): Ch11, scanning is performed in the order of the profile having the highest priority (S128). Then, scanning is continued until communication is possible with any channel and profile (S116 to S120, S124 to 128).

Here, consider a case where the scan current of the mobile device of this embodiment is 1 A, and the scan time for each channel is 1 s. In this case, the total current consumption is as follows.
Maximum total current consumption = 2Ch x 1s x 1A x 3 profiles
= 6As
Minimum total current consumption = 1Ch x 1s x 1A x 1 profile
= 1 As

  That is, in the mobile device according to the present embodiment, a channel that has a high possibility of being connected to a predetermined threshold or higher is predicted in advance, and only that channel is scanned. There is a possibility. Furthermore, there is a possibility that the time for scanning can be shortened as compared with the conventional method.

  Hereinafter, the mobile device according to the second embodiment of the present invention will be described. FIG. 6 is a table showing the order of scanning according to the second embodiment of the present invention, and FIG. 9 is a flowchart showing handover in the second embodiment of the present invention. In the first embodiment, the channels with the strongest radio field strength are sequentially scanned from the profile with the highest priority. However, in this embodiment, priority is given to performing communication with the profile with the higher priority, and the threshold value is exceeded. For all channels determined to have a radio field strength of, scanning is performed with a higher priority profile, and when communication is impossible, scanning is performed with a lower profile.

  In the present embodiment, similarly to the first embodiment, the radio field intensity determination mechanism 12 determines the radio field intensity for each channel, and the channel Ch (1) having the highest radio field intensity according to the highest priority profile P (1). : Ch14 is scanned first, and it is determined whether or not communication is possible. If communication is possible, the channel and the profile are connected (S210 to S222).

If communication is impossible, the priority is highest in the channel Ch (m) having a lower radio wave intensity rank than the radio wave intensity rank m = m + 1, that is, in the channel Ch (2): Ch11 as shown in FIG. Scanning is performed using the upper profile P (1) (S226). When m = m _max , that is, after scanning all the channels whose radio field intensity is equal to or greater than the threshold (S224), the lower priority order n = n + 1 profile, that is, as shown in FIG. A similar scan is performed using the profiles P (2) and P (3) (S228). Scanning is continued until communication is possible with any channel and profile (S216 to S220, S224 to 228).

  In this embodiment, in addition to the advantage of scanning only channels with radio field strengths above the threshold, the channels with radio field strengths above the threshold are scanned in order of the profile with the highest priority. There is an advantage that the possibility that communication can be performed by the profile is increased.

  The mobile device of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in order to increase the efficiency of scanning, it is possible to slow down the scanning order with the combination of channels and profiles that belonged before handover, or the combination of channels and profiles that belonged before handover It is also possible to scan with a combination of channels and profiles other than.

It is a figure which shows the structure of the moving apparatus which concerns on 1st Embodiment of this invention. It is a table | surface which shows the relationship between the priority of the channel which concerns on 1st Embodiment of this invention, and the electromagnetic wave intensity for every channel. It is a figure which shows the example of the hand-over of the mobile device in 1st Embodiment of this invention. It is a table | surface which shows the order of the scan in the conventional mobile apparatus. It is a table | surface which shows the order of the scan which concerns on 1st Embodiment of this invention. It is a table | surface which shows the order of the scan which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the hand-over in the conventional mobile apparatus. It is a flowchart which shows the hand-over in 1st Embodiment of this invention. It is a flowchart which shows the hand-over in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mobile device, 12 ... Radio wave intensity determination mechanism, 14 ... Memory | storage mechanism, 16 ... Scan execution part, 18 ... Control part, 20, 22, 24, 26 ... Access point

Claims (2)

In a communication network composed of a plurality of base stations, a mobile device that performs wireless communication via the base station,
A radio field strength judging mechanism for judging the radio field strength of each channel from the base station;
A storage mechanism for storing a profile for performing wireless communication with the base station;
A scan execution unit that scans whether or not communication is possible according to a profile stored in the storage mechanism for only a channel determined to have a radio field intensity equal to or higher than a threshold by the radio field intensity determination mechanism at the time of handover,
With
The storage mechanism stores a higher-order profile and a lower-order profile,
The scan execution unit
For channels determined to have a radio field intensity equal to or higher than the threshold , first , scanning is performed according to the higher profile in descending order of radio field intensity determined by the radio field intensity determination mechanism , and scanning is continued until communication is possible. When communication is possible by any of the channels determined to have the above radio wave intensity, communication is performed with the channel and the upper profile,
When not communicate by said host profile by all channels is determined that radio field intensity equal to or greater than the threshold value, the determination channel with the threshold value or more radio wave intensity, radio field intensity is determined by the radio wave intensity determination mechanism In order from the highest, the lower profile is scanned, and the scan is continued until communication is possible, and when communication is possible using any of the channels determined to have a radio wave intensity equal to or higher than the threshold, the channel and the lower profile A mobile device that communicates with each other . In a communication network composed of a plurality of base stations, a mobile device communication method for performing wireless communication via the base station,
Determining the radio field intensity for each channel from the base station;
Storing a profile for performing wireless communication with the base station;
Scanning whether or not communication is possible according to the profile stored by the step of storing the profile for only the channel determined to have a radio field intensity equal to or higher than a threshold by the step of determining the radio field intensity at the time of handover;
Including
In the step of storing the profile, a higher priority profile and a lower profile are stored,
In the step of scanning whether or not communication is possible,
For the channel determined to have a radio field intensity equal to or greater than the threshold, in order from the highest radio field intensity determined by the step of determining the radio field intensity, first scan by the higher profile, and continue scanning until communication is possible, When communication is possible with any of the channels determined to have a radio field intensity equal to or higher than the threshold, the channel and the higher profile communicate with each other.
When not communicate by said host profile by all channels is determined that radio field intensity equal to or greater than the threshold value, the determination channel with the threshold value or more radio field intensity, have rows scanned by the lower profile, communication A communication method of a mobile device that continues scanning until it becomes possible and communicates with the channel and the lower profile when communication is possible through any of the channels determined to have a radio field intensity equal to or greater than the threshold .

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