U.S. patent application number 13/409794 was filed with the patent office on 2012-06-28 for access point terminal, wireless communication terminal, wireless communication system, wireless communication method, program and integrated circuit.
Invention is credited to Nobuhiko ARASHIN, Masahiko Nagoshi, Akihiko Shiotsuki, Osamu Tanaka, Toyoshi Yamada, Akira Yamasaki.
Application Number | 20120163324 13/409794 |
Document ID | / |
Family ID | 45371157 |
Filed Date | 2012-06-28 |
United States Patent
Application |
20120163324 |
Kind Code |
A1 |
ARASHIN; Nobuhiko ; et
al. |
June 28, 2012 |
ACCESS POINT TERMINAL, WIRELESS COMMUNICATION TERMINAL, WIRELESS
COMMUNICATION SYSTEM, WIRELESS COMMUNICATION METHOD, PROGRAM AND
INTEGRATED CIRCUIT
Abstract
An access point terminal includes: a wireless communication
interface which transmits and receives a wireless signal; a device
information obtaining unit which obtains supported frequency
information through the wireless communication interface, the
supported frequency information being for specifying one or more
frequency bands in which the wireless communication terminal is
capable of performing wireless communication; and a connection
information distribution unit which (i) selects a frequency band
out of the one or more frequency bands indicated in the supported
frequency information obtained by the device information obtaining
unit and (ii) distributes connection information to the wireless
communication terminal through the wireless communication
interface, the connection information being for causing the
wireless communication terminal to perform the wireless
communication in the selected frequency band.
Inventors: |
ARASHIN; Nobuhiko; (Osaka,
JP) ; Tanaka; Osamu; (Osaka, JP) ; Yamada;
Toyoshi; (Osaka, JP) ; Nagoshi; Masahiko;
(Osaka, JP) ; Shiotsuki; Akihiko; (Osaka, JP)
; Yamasaki; Akira; (Osaka, JP) |
Family ID: |
45371157 |
Appl. No.: |
13/409794 |
Filed: |
March 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP2011/003534 |
Jun 21, 2011 |
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13409794 |
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Current U.S.
Class: |
370/329 ;
370/338 |
Current CPC
Class: |
H04W 72/0453 20130101;
H04W 48/08 20130101; H04W 72/048 20130101; H04W 72/085 20130101;
H04W 72/0406 20130101; H04W 88/08 20130101; H04W 72/02
20130101 |
Class at
Publication: |
370/329 ;
370/338 |
International
Class: |
H04W 84/02 20090101
H04W084/02; H04W 88/08 20090101 H04W088/08; H04W 72/04 20090101
H04W072/04; H04W 88/02 20090101 H04W088/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2010 |
JP |
2010-141045 |
Claims
1. An access point terminal which performs wireless communication
with a wireless communication terminal, said access point terminal
comprising: a wireless communication interface which transmits and
receives a wireless signal; a device information obtaining unit
configured to obtain supported frequency information through said
wireless communication interface, the supported frequency
information being for specifying one or more frequency bands in
which the wireless communication terminal is capable of performing
wireless communication; and a connection information distribution
unit configured to (i) select a frequency band out of the one or
more frequency bands indicated in the supported frequency
information obtained by said device information obtaining unit, and
(ii) distribute connection information to the wireless
communication terminal through said wireless communication
interface, the connection information being for causing the
wireless communication terminal to perform the wireless
communication in the selected frequency band.
2. The access point terminal according to claim 1, wherein the
wireless communication terminal transmits, to said access point
terminal, a wireless communication start request signal for
requesting a start of the wireless communication with said access
point terminal, using each of the one or more frequency bands in
which the wireless communication terminal is capable of performing
wireless communication, and said device information obtaining unit
is configured to obtain, as the supported frequency information,
each of the one or more frequency bands used for transmitting a
corresponding one of the one or more wireless communication start
request signals received through said wireless communication
interface.
3. The access point terminal according to claim 2, wherein said
wireless communication interface is further configured to measure
magnitude of received power of each of the one or more wireless
communication start request signals received from the wireless
communication terminal, and said connection information
distribution unit is configured to select a frequency band in which
the received power measured by said wireless communication
interface is the highest, out of the one or more frequency
bands.
4. The access point terminal according to claim 1, wherein said
wireless communication interface is further configured to measure
an interference state of each of the one or more frequency bands,
and said connection information distribution unit is configured to
select a frequency band in which the interference state measured by
said wireless communication interface is less than a predetermined
threshold, out of the one or more frequency bands indicated in the
supported frequency information.
5. The access point terminal according to claim 1, wherein the
wireless communication terminal transmits, to said access point
terminal, a device information transmission signal including a
desired frequency band which is desired for use in the wireless
communication with said access point terminal, and said device
information obtaining unit is configured to obtain, as the
supported frequency information, the desired frequency band
included in the device information transmission signal received
through said wireless communication interface.
6. The access point terminal according to claim 1, wherein the
wireless communication terminal transmits, to said access point
terminal, the device information transmission signal including
information indicating a type of the wireless communication
terminal, and said access point terminal includes a conversion
table which holds (i) pieces of information each indicating a
different type of the wireless communication terminal and (ii)
frequency bands each of which is to be allocated to the wireless
communication terminal of the corresponding type, such that
corresponding ones of the pieces of information and the frequency
bands are associated with each other, and said device information
obtaining unit is configured to select a frequency band associated
with the information indicating the type that is included in the
device information transmission signal received through the
wireless communication terminal, the frequency band being included
in frequency bands held in the conversion table.
7. A wireless communication terminal which performs wireless
communication with an access point terminal, using one of a
plurality of frequency bands, said wireless communication terminal
comprising: a wireless communication interface which (i) transmits
and receives a wireless signal using each of the frequency bands
and (ii) measures a reception state of each of the frequency bands;
and a device-information-exchange control unit configured to (i)
transmit a device information transmission signal including a
desired frequency band to said access point terminal through said
wireless communication interface and (ii) obtain connection
information from said access point terminal through said wireless
communication interface, the desired frequency band being desired
for use in the wireless communication with said access point
terminal, and the connection information being for performing
wireless communication in the desired frequency band, wherein said
device-information-exchange control unit is configured to
determine, as the desired frequency band, a frequency band in which
the reception state measured by said wireless communication
interface is the best, out of the frequency bands.
8. A wireless communication system comprising an access point
terminal and a wireless communication terminal, wherein said access
point terminal includes: a first wireless communication interface
which transmits and receives a wireless signal; a device
information obtaining unit configured to obtain supported frequency
information through said first wireless communication interface,
the supported frequency information being for specifying one or
more frequency bands in which the wireless communication terminal
is capable of performing wireless communication; and a connection
information distribution unit configured to (i) select a frequency
band out of the one or more frequency bands indicated in the
supported frequency information obtained by said device information
obtaining unit and (ii) distribute connection information to the
wireless communication terminal through said first wireless
communication interface, the connection information being for
causing the wireless communication terminal to perform the wireless
communication in the selected frequency band, wherein said wireless
communication terminal includes: a second wireless communication
interface which transmits and receives the wireless signal; and a
device-information-exchange control unit configured to (i) transmit
the supported frequency information to said access point terminal
through said second wireless communication interface and (ii)
receive the connection information from said access point terminal
through said second wireless communication interface.
9. A method of performing wireless communication with a wireless
communication terminal, performed by an access point terminal
including a wireless communication interface which transmits and
receives a wireless signal, said method comprising: obtaining
supported frequency information through said wireless communication
interface, the supported frequency information being for specifying
one or more frequency bands in which the wireless communication
terminal is capable of performing wireless communication; and
selecting a frequency band out of the one or more frequency bands
indicated in the supported frequency information obtained in said
obtaining, and distributing the connection information to the
wireless communication terminal through the wireless communication
interface, the connection information being for causing the
wireless communication terminal to perform the wireless
communication in the selected frequency band.
10. A method of performing wireless communication with an access
point terminal, performed by a wireless communication terminal
having a wireless communication interface which (i) transmits and
receives a wireless signal using one of a plurality of frequency
bands and (ii) measures a reception state of each of the frequency
bands, said method comprising: transmitting a device information
transmission signal to the access point terminal through the
wireless communication interface, the device information
transmission signal including a desired frequency band which is
desired for use in the wireless communication with the access point
terminal; and obtaining the connection information from the access
point terminal through the wireless communication interface, the
connection information being for performing the wireless
communication in the desired frequency band, wherein, in said
transmitting, a frequency band in which the reception state
measured by the wireless communication interface is the best, out
of the frequency bands; is determined as the desired frequency
band.
11. A non-transitory computer-readable recording medium for use in
a computer and on which a program is recorded, the program being
for causing the computer having a wireless communication interface
which transmits and receives a wireless signal to perform wireless
communication with a wireless communication terminal, and the
program causing the computer to execute: obtaining supported
frequency information through the wireless communication interface,
the supported frequency information being for specifying one or
more frequency bands in which the wireless communication terminal
is capable of performing wireless communication; and selecting a
frequency band out of the one or more frequency bands indicated in
the supported frequency information obtained in said obtaining, and
distributing connection information to the wireless communication
terminal through the wireless communication interface, the
connection information being for causing the wireless communication
terminal to perform the wireless communication in the selected
frequency band.
12. A non-transitory computer-readable recording medium for use is
in a computer and on which a program is recorded, the program being
for causing the computer including a wireless communication
interface which (i) transmits or receives a wireless signal using
one of a plurality of frequency bands and (ii) measures a reception
state of each of the frequency bands, to perform wireless
communication with an access point terminal using one of a
plurality of frequency bands, and the program causing the computer
to execute: transmitting a device information transmission signal
to the access point terminal through the wireless communication
interface, the device information transmission signal including a
desired frequency band which is desired for use in the wireless
communication with the access point terminal; and obtaining the
connection information from the access point terminal through the
wireless communication interface, the connection information being
for performing the wireless communication in the desired frequency
band, wherein, in said transmitting, a frequency band in which the
reception state measured by the wireless communication interface is
the best, out of the frequency bands, is determined as the desired
frequency band.
13. An integrated circuit which performs wireless communication
with a wireless communication terminal, said integrated circuit
comprising: a wireless communication interface which transmits and
receives a wireless signal; a device information obtaining unit
configured to obtain supported frequency information through the
wireless communication interface, the supported frequency
information being for specifying one or more frequency bands in
which the wireless communication terminal is capable of performing
wireless communication; and a connection information distribution
unit configured to (i) select a frequency band out of the one or
more frequency bands indicated in the supported frequency
information obtained by said device information obtaining unit and
(ii) distribute connection information to the wireless
communication terminal through the wireless communication
interface, the connection information being for causing the
wireless communication terminal to perform the wireless
communication in the selected frequency band.
14. An integrated circuit which performs wireless communication
with an access point terminal, using one of a plurality of
frequency bands, said integrated circuit comprising: a wireless
communication interface which (i) transmits and receives a wireless
signal using each of the frequency bands and (ii) measures a
reception state of each of the frequency bands; and a
device-information-exchange control unit configured to (i) transmit
a device information transmission signal including a desired
frequency band to said access point terminal through said wireless
communication interface and (ii) obtain connection information from
the access point terminal through said wireless communication
interface, the desired frequency band being desired for use in the
wireless communication with said access point terminal, and the
connection information being for performing wireless communication
in the desired frequency band, wherein said
device-information-exchange control unit is configured to
determine, as the desired frequency band, a frequency band in which
the reception state measured by said wireless communication
interface is the best, out of the frequency bands.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This is a continuation application of PCT application No.
PCT/JP2011/003534 filed on Jun. 21, 2011, designating the United
States of America, which is based on and claims priority of
Japanese Patent Application No. 2010-141045 filed on Jun. 21, 2010.
The entire disclosures of the above-identified applications,
including the specifications, drawings and claims are incorporated
herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] (1) Field of the Invention
[0003] The present invention relates to information processing
techniques, and particularly to an information processing technique
that enables efficient use of a band in wireless communication.
[0004] (2) Description of the Related Art
[0005] In recent years, many devices which can be used with
wireless LANs are commercialized and it is possible to use various
applications with ease and convenience. Furthermore, it is known
that the advent of Institute of Electrical and Electronics
Engineers (IEEE) 802.11n has allowed a faster and more stable
wireless communication, and thus, for example, streaming of a
high-image-quality video can be performed at home using Digital
Living Network Alliance (DLNA).
[0006] However, as the number of wireless LAN devices increases,
there are cases where a user cannot execute a service smoothly
because a band available for a wireless LAN device is overwhelmed.
Furthermore, in a 2.4 GHz band, there is a problem that radio wave
interference frequently occurs when the band is used by various
device's, because the 2.4 GHz band is an Industry Science Medical
(ISM) band.
[0007] Therefore, in general, a 5 GHz band with less interference
is used for a wireless signal that requires high real-timeliness,
such as that for video. In contrast, the 2.4 GHz band is sufficient
for use in content downloading or web browsing. However, if all
terminals are connected through the 5 GHz band as there is less
interference, the 5 GHz band becomes overwhelmed, which is like
putting the cart before the horse. Therefore, it is preferable to
determine which of the 2.4 GHz band and the 5 GHz band to use,
depending on the level of real-timeliness required for the wireless
communication.
[0008] As a technique for using such wireless bands efficiently,
there is known a line acquisition method for a wireless IP phone
service using a wireless LAN that controls the wireless band, by
(i) controlling wireless IP phones connected to SSIDs in an
integrated manner as shown in FIG. 25 and (ii) restricting a
communication traffic volume to be equal to or less than a
threshold set for SSIDs of an access point terminal (see Patent
Literature 1: Japanese Unexamined Patent Application Publication
No. 2007-214657).
[0009] However, with the effective usage of wireless LAN band in
the line acquisition method having the configuration described
above, the communication traffic volume per se is restricted
equally for all of the terminals. Therefore, a band is
unnecessarily allocated to a terminal which is not requiring a
band, which makes it impossible to properly allocate a band for a
terminal which is requiring a band. Furthermore, restricting a
communication traffic volume is not always effective, since in
general a wireless band cannot be quantitatively manipulated. The
present invention has been conceived in view of the above-described
conventional problems and aims to provide an access point terminal
capable of improving an efficiency in use of the wireless band, by
causing a terminal to be connected in an appropriate operating
frequency band.
SUMMARY OF THE INVENTION
[0010] An access point terminal according to an aspect of the
present invention performs wireless communication with a wireless
communication terminal. Specifically, the access point terminal
includes: a wireless communication interface which transmits and
receives a wireless signal; a device information obtaining unit
which obtains supported frequency information through the wireless
communication interface, the supported frequency information being
for specifying one or more frequency bands in which the wireless
communication terminal is capable of performing wireless
communication; and a connection information distribution unit which
(i) selects a frequency band out of the one or more frequency bands
indicated in the supported frequency information obtained by the
device information obtaining unit and (ii) distributes connection
information to the wireless communication terminal through the
wireless communication interface, the connection information being
for causing the wireless communication terminal to perform the
wireless communication in the selected frequency band.
[0011] The above configuration allows to (i) select an appropriate
frequency band for each of the wireless communication terminals and
(ii) distribute connection information of the selected frequency
band. That is, the access point terminal above enables to allocate
(i) a frequency band with less interference (for example, the 5 GHz
band) to a wireless communication terminal requiring high
real-timeliness in the wireless communication and (ii) other
frequency band (for example, the 2.4 GHz band) to the wireless
communication terminal other than the wireless communication
terminal.
[0012] The wireless communication terminal may further transmit, to
the access point terminal, a wireless communication start request
signal for requesting a start of the wireless communication with
the access point terminal, using each of the one or more frequency
bands in which the wireless communication terminal is capable of
performing wireless communication. The device information obtaining
unit may obtain, as the supported frequency information, each of
the one or more frequency bands used for transmitting a
corresponding one of the one or more wireless communication start
request signals received through the wireless communication
interface.
[0013] The above configuration allows to (i) select an appropriate
frequency band for a conventional wireless communication terminal
as well and (ii) distribute connection information of the selected
frequency band, without defining a new wireless signal for
transmitting the supported frequency information.
[0014] The wireless communication interface may further measure
magnitude of received power of each of the one or more wireless
communication start request signals received from the wireless
communication terminal. The connection information distribution
unit may select a frequency band in which the received power
measured by the wireless communication interface is the highest,
out of the one or more frequency bands.
[0015] This allows to select an appropriate frequency band with the
best reception state. That is, this allows to select an appropriate
operation frequency depending on communication environment.
[0016] The wireless communication interface may further measure an
interference state of each of the one or more frequency bands. The
connection information distribution unit may select a frequency
band in which the interference state measured by the wireless
communication interface is less than a predetermined threshold, out
of the one or more frequency bands indicated in the supported
frequency information.
[0017] This allows to select an appropriate frequency band with the
best reception state. That is, this allows to select an appropriate
operation frequency depending on communication environment.
[0018] The wireless communication terminal may transmit, to the
access point terminal, a device information transmission signal
including a desired frequency band which is desired for use in the
wireless communication with the access point terminal. The device
information obtaining unit may obtain, as the supported frequency
information, the desired frequency band included in the device
information transmission signal received through the wireless
communication interface.
[0019] The above configuration permits communication in a frequency
band desired for use by each of the wireless communication
terminals, and allows to use a frequency band depending on a state
of each of the wireless communication terminals.
[0020] Furthermore, the wireless communication terminal may
transmit, to the access point terminal, the device information
transmission signal including information indicating a type of the
wireless communication terminal. The access point terminal may
include a conversion table which holds (i) pieces of information
each indicating a different type of the wireless communication
terminal and (ii) frequency bands each of which is to be allocated
to the wireless communication terminal of the corresponding type,
such that corresponding ones of the pieces of information and the
frequency bands are associated with each other. The device
information obtaining unit may select a frequency band associated
with the information indicating the type that is included in the
device information transmission signal received through the
wireless communication terminal, the frequency band being included
in frequency bands held in the conversion table.
[0021] A wireless communication terminal according to an aspect of
the present invention performs wireless communication with an
access point terminal, using one of a plurality of frequency bands.
Specifically, the wireless communication terminal includes: a
wireless communication interface which (i) transmits and receives a
wireless signal using each of the frequency bands and (ii) measures
a reception state of each of the frequency bands; and a
device-information-exchange control unit which (i) transmits a
device information transmission signal including a desired
frequency band to the access point terminal through the wireless
communication interface and (ii) obtains connection information
from the access point terminal through the wireless communication
interface, the desired frequency band being desired for use in the
wireless communication with the access point terminal, and the
connection information being for performing wireless communication
in the desired frequency band. The device-information-exchange
control unit determines, as the desired frequency band, a frequency
band in which the reception state measured by the wireless
communication interface is the best, out of the frequency
bands.
[0022] The above configuration allows a communication in a
frequency band desired for use by each of the wireless
communication terminals.
[0023] A wireless communication system according to the present
invention includes an access point terminal and a wireless
communication terminal. The access point terminal includes: a first
wireless communication interface which transmits and receives a
wireless signal; a device information obtaining unit which obtains
supported frequency information through the first wireless
communication interface, the supported frequency information being
for specifying one or more frequency bands in which the wireless
communication terminal is capable of performing wireless
communication; and a connection information distribution unit which
(i) selects a frequency band out of the one or more frequency bands
indicated in the supported frequency information obtained by the
device information obtaining unit and (ii) distributes connection
information to the wireless communication terminal through the
first wireless communication interface, the connection information
being for causing the wireless communication terminal to perform
the wireless communication in the selected frequency band. The
wireless communication terminal includes: a second wireless
communication interface which transmits and receives the wireless
signal; and a device-information-exchange control unit which (i)
transmits the supported frequency information to the access point
terminal through the second wireless communication interface and
(ii) receives the connection information from the access point
terminal through the second wireless communication interface.
[0024] A wireless communication method according to an aspect of
the present invention is a method of performing wireless
communication with a wireless communication terminal performed by
an access point terminal including a wireless communication
interface which transmits and receives a wireless signal.
Specifically, the method includes: obtaining supported frequency
information through the wireless communication interface, the
supported frequency information being for specifying one or more
frequency bands in which the wireless communication terminal is
capable of performing wireless communication; and selecting a
frequency band out of the one or more frequency bands indicated in
the supported frequency information obtained in the obtaining, and
distributing the connection information to the wireless
communication terminal through the wireless communication
interface, the connection information being for causing the
wireless communication terminal to perform the wireless
communication in the selected frequency band.
[0025] A wireless communication method according to other aspects
of the present invention is a method of performing wireless
communication with an access point terminal, performed by a
wireless communication terminal having a wireless communication
interface in which (i) transmits and receives a wireless signal
using one of a plurality of frequency bands and (ii) measures a
reception state of each of the frequency bands. Specifically, the
method includes: transmitting a device information transmission
signal to the access point terminal through the wireless
communication interface, the device information transmission signal
including a desired frequency band which is desired for use in the
wireless communication with the access point terminal; and
obtaining the connection information from the access point terminal
through the wireless communication interface, the connection
information being for performing the wireless communication in the
desired frequency band. In the transmitting, a frequency band in
which the reception state measured by the wireless communication
interface is the best, out of the frequency bands, is determined as
the desired frequency band.
[0026] A non-transitory computer-readable recording medium for use
in a computer according to an aspect of the present invention is
recorded with a program for causing the computer having a wireless
communication interface which transmits and receives a wireless
signal to perform wireless communication with a wireless
communication terminal. Specifically, the program causes the
computer to execute: obtaining supported frequency information
through the wireless communication interface, the supported
frequency information being for specifying one or more frequency
bands in which the wireless communication terminal is capable of
performing wireless communication; and selecting a frequency band
out of the one or more frequency bands indicated in the supported
frequency information obtained in the obtaining, and distributing
connection information to the wireless communication terminal
through the wireless communication interface, the connection
information being for causing the wireless communication terminal
to perform the wireless communication in the selected frequency
band.
[0027] A non-transitory computer-readable recording medium for use
in a computer according to other aspects of the present invention
is recorded with a program for causing the computer including a
wireless communication interface which (i) transmits or receives a
wireless to signal using one of a plurality of frequency bands and
(ii) measures a reception state of each of the frequency bands, to
perform wireless communication with an access point terminal using
one of a plurality of frequency bands. Specifically, the program
causes the computer to execute: transmitting a device information
transmission signal to the access point terminal through the
wireless communication interface, the device. information
transmission signal including a desired frequency band which is
desired for use in the wireless communication with the access point
terminal; and obtaining the connection information from the access
point terminal through the wireless communication interface, the
connection information being for performing the wireless
communication in the desired frequency band. In the transmitting, a
frequency band in which the reception state measured by the
wireless communication interface is the best, out of the frequency
bands, is determined as the desired frequency band.
[0028] An integrated circuit according to an aspect of the present
invention performs wireless communication with a wireless
communication terminal. Specifically, the integrated circuit
includes: a wireless communication interface which transmits and
receives a wireless signal; a device information obtaining unit
which obtains supported frequency information through the wireless
communication interface, the supported frequency information being
for specifying one or more frequency bands in which the wireless
communication terminal is capable of performing wireless
communication; and a connection information distribution unit which
(i) selects a frequency band out of the one or more frequency bands
indicated in the supported frequency information obtained by the
device information obtaining unit, and (ii) distributes connection
information to the wireless communication terminal through the
wireless communication interface, the connection information being
for causing the wireless communication terminal to perform the
wireless communication in the selected frequency band.
[0029] An integrated circuit according to other aspects of the
present invention performs wireless communication with an access
point terminal using one of a plurality of frequency bands.
Specifically, the integrated circuit includes: a wireless
communication interface which (i) transmits and receives a wireless
signal using each of the frequency bands and (ii) measures a
reception state of each of the frequency bands; and a
device-information-exchange control unit which (i) transmits a
device information transmission signal including a desired
frequency band to the access point terminal through the wireless
communication interface and (ii) obtains connection information
from the access point terminal through the wireless communication
interface, the desired frequency band being desired for use in the
wireless communication with the access point terminal, and the
connection information being for performing wireless communication
in the desired frequency band. The device-information-exchange
control unit determines, as the desired frequency band, a frequency
band in which the reception state measured by the wireless
communication interface is the best, out of the frequency
bands.
[0030] The present invention enables an efficient use of the
frequency bands by causing the terminal to be connected in the
appropriate operating frequency band, thereby provide a wireless
LAN environment appropriate for the usage of the wireless
communication terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] These and other objects, advantages and features of the
invention will become apparent from the following description
thereof taken in conjunction with the accompanying drawings that
illustrate specific embodiments of the present invention. In the
Drawings:
[0032] FIG. 1 is a configuration diagram of a wireless
communication system according to a first embodiment of the present
invention;
[0033] FIG. 2 is a functional block diagram of an access point
terminal according to the first embodiment of the present
invention;
[0034] FIG. 3 is a flowchart of an operation of the access point
terminal according to the first embodiment of the present
invention;
[0035] FIG. 4 is a sequence diagram between the access point
terminal and a wireless communication terminal in a connection
information distribution process;
[0036] FIG. 5 shows data structure of a device information
transmission signal;
[0037] FIG. 6 shows a "Primary Device Type" of the device
information transmission signal;
[0038] FIG. 7A shows an example of a supported frequency band,
included in device information transmission signal received from
each of the wireless communication terminals;
[0039] FIG. 7B shows an example of a desired frequency band,
included in the device information transmission signal received by
each of the wireless communication terminals;
[0040] FIG. 8A shows an example of a conversion table which holds
(i) a Primary Device Type and (ii) an operation frequency band, of
a wireless communication terminal, such that the Primary Device
Type and the operation frequency are associated with each
other;
[0041] FIG. 8B shows an example of the operation frequency
allocated to each of the wireless communication terminals, based on
the conversion table in FIG. 8A;
[0042] FIG. 9A shows an example of a conversion table which holds
(i) a category and (ii) the operation frequency, of a wireless
communication terminal, such that the category and the operation
frequency are associated with each other;
[0043] FIG. 9B shows an example of the operation frequency
allocated to each of the wireless communication terminals, based on
the conversion table in FIG. 9A;
[0044] FIG. 10A shows an example of a communication start request
signal received by the access point terminal in a 2.4 GHz band;
[0045] FIG. 10B shows an example of the communication start request
signal received by the access point terminal in a 5 GHz band;
[0046] FIG. 11 shows an example of the communication start request
signal for each of the frequency bands and a received power of each
communication start request signal;
[0047] FIG. 12 shows an example of the communication start request
signal and an interference state for each of the frequency
bands;
[0048] FIG. 13 shows an example of communication terminal
information held by the access point terminal according to the
first embodiment of the present invention;
[0049] FIG. 14 is a flowchart showing a change of the SSID of the
access point terminal according to the first embodiment of the
present invention;
[0050] FIG. 15 shows an example of the communication terminal
information after the transfer of SSID held by the access point
terminal according to the first embodiment of the present invention
is moved;
[0051] FIG. 16 shows an example of the communication terminal
information held by the access point terminal according to an
second embodiment of the present invention;
[0052] FIG. 17 is a flowchart showing a change of the SSID of the
access point terminal according to the second embodiment of the
present invention;
[0053] FIG. 18 shows an example of the communication terminal
information after the transfer of the SSID, held by the access
point terminal according to the second embodiment of the present
invention;
[0054] FIG. 19 shows a field structure of an IP packet;
[0055] FIG. 20 is a flowchart showing a change of the SSID of the
access point terminal according to an third embodiment of the
present invention;
[0056] FIG. 21 is a flowchart showing a change of the SSID of the
access point terminal according to an fourth embodiment of the
present invention;
[0057] FIG. 22 is a functional block diagram of the access point
terminal according to an fifth embodiment of the present
invention;
[0058] FIG. 23 is a flowchart showing an operation of the access
point terminal according to the fifth embodiment of the present
invention;
[0059] FIG. 24 is a flowchart showing a change of the SSID of the
access point terminal according to the fifth embodiment of the
present invention; and
[0060] FIG. 25 shows a conventional technique.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0061] Embodiments of the present invention are described below
with reference to drawings.
First Embodiment
[0062] First, a configuration diagram of a wireless LAN system
according to a first embodiment is described. The wireless LAN
system according to the first embodiment includes an access point
terminal 1 (hereinafter referred to as AP) and wireless
communication terminals 2 to 5 (hereinafter referred to as STA).
The STA2 to the STA5 are connected using an infrastructure mode and
communicate under a control of the AP1. The number of the STAs is 4
in the first embodiment, however, it goes without saying that it is
not limited to the number.
[0063] Furthermore, the STA2 to the STA5 are connected with the AP1
using Wi-Fi Protected Setup (WPS), which is an easy setup for
wireless LAN advocated by Wi-Fi Alliance (WFA). It goes without
saying that, without being limited to WPS, other easy connections
for wireless LAN may be used, such as the easy connection which (i)
enables an automatic key exchange between the AP1 and each of the
STA2 to the STA5, and (ii) allows the AP1 to distribute connection
information to the STA2 to the STA5.
[0064] Furthermore, it is assumed that the AP1 is a device which is
capable of concurrently operating in frequency bands (for example,
in the 2.4 GHz band and the 5 GHz band). Furthermore, although the
2.4 GHz band and the 5 GHz band include channels, it is assumed
that the AP1 according to this embodiment performs (i) wireless
communication in the 2.4 GHz band through a channel 1 (1ch) and
(ii) the wireless communication in the 5 GHz band through a channel
36 (36ch). Furthermore, the STA2 to the STA4 are devices capable of
(i) selecting one of the 2.4 GHz band and the 5 GHz band and (ii)
connecting to a channel in a frequency band in which the AP1 is
operating. Meanwhile, the STA5 is assumed to be a device which
operates only in the 2.4 GHz band.
[0065] When WPS is performed between the AP1, the STA2 to the STA4
are connected with the AP1 in the 5 GHz band that is with less
interference. The STA5 is connected with the AP1 in the 2.4 GHz
band, because the STA5 does not support the 5 GHz band.
[0066] The STA2 to the STA5 communicate under the control of the
AP1, and are capable of executing various applications. For
example, the STA2 to the STA5 are capable of (i) executing services
from the Internet via the AP1 and (ii) executing applications such
as DLNA among the STAs.
[0067] Next, the configuration of the AP1 is described with
reference to FIG. 2.
[0068] The AP1 includes, as shown in FIG. 2, a wireless
communication interface 11, a device-information-exchange control
unit 10, a connection information distribution unit 12, a
connection information management unit 13, a communication terminal
management unit 9, an SSID issuance management unit 7, a
communication-terminal-status determination unit 6, and a frequency
control unit 8.
[0069] The wireless communication interface 11 is an interface for
transmitting and receiving a wireless signal between the wireless
communication terminals. That is, the wireless communication
interface 11 transmits, as a wireless signal, data generated by the
device-information-exchange control unit 10, the connection
information distribution unit 12, or the like, to each of the STA2
to the STA5. Furthermore, the wireless communication interface 11
generates data from a wireless signal received from the STA2 to the
STA5, and notifies the generated data to the
communication-terminal-status determination unit 6, the
device-information-exchange control unit 10, or the like.
Furthermore, the wireless communication interface 11 measures a
received power of the received wireless signal, or a reception
state, such as an interference state, of each of the frequency
bands. Moreover, the wireless communication interface 11 transmits,
in a predetermined time interval, a beacon signal to each of the
wireless communication terminals managed by the communication
terminal management unit 9.
[0070] The beacon signal includes a Service Set Identifier (SSID)
which is assigned to a destination wireless communication terminal,
and is transmitted using the frequency band used for wireless
communication with the wireless communication terminal. The SSID of
each of the wireless communication terminals and the frequency band
to be used by each of the wireless communication terminals are held
by the communication terminal management unit 9.
[0071] The device-information-exchange control unit (device
information obtaining unit) 10 exchanges the device information
between the wireless communication terminals which newly request a
start of the wireless communication. That is, the
device-information-exchange control unit 10 (i) transmits the
device information of the AP1 to the communication terminal which
newly requests a start of the wireless communication and (ii)
obtains the device information of the communication terminal which
newly requests the start of the wireless communication.
[0072] The connection information management unit 13 holds
information required by the wireless communication terminal for
performing the wireless communication with the AP1. Specifically,
the connection information management unit 13 holds key information
for coding and decoding the wireless signal. In a description on an
example below, it is assumed that the connection information
management unit 13 holds the key information in the 5 GHz band (the
first frequency band) and the key information in the 2.4 GHz band
(the frequency band other than the first frequency band).
[0073] It is to be noted that the description below is based on an
assumption that the first frequency band is the 5 GHz band and the
frequency band other than the first frequency band is the 2.4 GHz
band, however, the present invention is not limited to the above.
That is, it is sufficient when the first and the second frequency
bands are frequency bands different from each other. Typically, the
first frequency band is a frequency band which is higher than the
other frequency band and with less interference, however, the
present invention is not limited to the above. Furthermore, the
frequency band may be equal to or more than three. o The connection
information distribution unit 12 transmits the connection
information (key information) held by the connection information
management unit 13 to the wireless communication terminal which
newly requests a start of the wireless communication. It is to be
noted that a method of selecting the connection information to be
transmitted is not specifically limited and, for example, the
following method may be used.
[0074] For example, the connection information distribution unit 12
may distribute, to the wireless communication terminal, all the
connection information held by the connection information
management unit 13 to cause the wireless communication terminal to
select which connection information (that is, which frequency band)
to use for the wireless communication. Alternatively, the
connection information distribution unit 12 may transmit only the
connection information associated with the frequency band used for
the WPS process. Moreover, when the obtained device information
includes information indicating one or more frequency bands
supported by the wireless communication terminal, the connection
information distribution unit 12 may transmit only the connection
information associated with single frequency band selected from the
one or more frequency bands.
[0075] The communication terminal management unit 9 holds
information of each of the wireless communication terminals
performing wireless communication between the AP1. For example, the
communication terminal management unit 9 holds (i) the SSID
assigned to the wireless communication terminal and (ii) the
frequency band being used for the wireless communication between
the wireless communication terminals, such that the SSID and the
frequency band is associated with each other. Details are described
later using FIG. 13.
[0076] The SSID issuance management unit 7 assigns an SSID to the
wireless communication terminal which newly requests a start of the
wireless communication. Regarding the method of assigning the SSID,
for example, the SSID issuance management unit 7 may assign a
unique SSID to (i) each of the wireless communication terminals,
(ii) each of the categories to which the wireless communication
terminals belong, or (iii) each of the channels which the wireless
communication terminals use.
[0077] The communication-terminal-status determination unit 6
determines the communication status of each of the wireless
communication terminals by obtaining the wireless signal
transmitted and received by each of the wireless communication
terminals, where the communication status includes a volume or a
quality of the communication.
[0078] As an example of the volume of the communication, the
traffic volume of the wireless signal is raised. Furthermore, as an
example of the quality of the communication, priority included in
the wireless signal, more specifically, a Type of Service (ToS) or
a DiffSery Code Point (DSCP) included in an IP header is
raised.
[0079] Moreover, the communication-terminal-status determination
unit 6 may determine (i) that the communication status satisfies a
condition, when an application execution notification is received,
and (ii) that the communication status has changed from a status
that satisfies the condition to a status that does not satisfy the
condition, when the application completion notification is
received, where the application execution notification indicates
that the execution of the application requiring higher
real-timeliness than a predetermined value in wireless
communication has started, and the application completion
notification indicates that the execution of the application
requiring the higher real-timeliness than a predetermined value in
wireless communication is completed.
[0080] The frequency control unit 8 performs a process of switching
between the frequency bands for use in the wireless communication
with each of the wireless communication terminals, according to the
communication status and so forth. For example, when the
communication-terminal-status determination unit 6 determines that
the communication status of the wireless communication terminal
satisfies a predetermined condition, the frequency control unit 8
uses the first frequency band for the wireless communication with
the wireless communication terminal, and uses the frequency band
other than the first frequency band for the wireless communication
with other communication terminals assigned with the SSID different
from the wireless communication terminal.
[0081] Specifically, the frequency control unit 8 is capable of
switching the frequency bands for use in the wireless communication
with the wireless communication terminal assigned with the SSID, by
changing the association between the SSID and the frequency band
held by the communication terminal management unit 9.
[0082] Next, an operation of the AP1 when the start of the wireless
communication is requested from the STA2 is described with
reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing steps of
a connection information distribution process. FIG. 4 is a sequence
diagram between the AP1 and the STA2 in the connection information
distribution process. It is to be noted that the AP1 operates in
the same manner as the above when the start of the wireless
communication is requested from the STA3 to the STA5.
[0083] First, the AP1 receives an instruction from a user
indicating that WPS is to be started between the STA2 (S101).
Specifically, upon a press of a button (WPS start button) provided
on each of the AP1 and the STA2, the STA2 transmits a communication
start request signal (Probe Request) to the AP1.
[0084] This is a process in which the STA2 searches the AP1, which
is to be the communication partner, and corresponds to the step 1
shown in FIG. 4. Specifically, the STA2 transmits the communication
start request signal to all of the channels in the 5 GHz band and
all of the channels in the 2.4 GHz band.
[0085] Meanwhile, the AP1 (i) receives a communication start
request signal from a channel that the AP1 uses, out of the
communication start request signals transmitted from the STA2 in
the 5 GHz band, and (ii) transmits a communication start response
signal (Probe Response) to the STA2. In the same manner, the AP1
(i) receives a communication start request signal from a channel
that the AP1 uses, out of the communication start request signals
transmitted from the STA2 in the 2.4 GHz band, and (ii) transmits a
communication start response signal to the STA2. It is to be noted
that the communication in start request signal and the
communication start response signal associated with each other are
transmitted and received using the same frequency band and the same
channel.
[0086] Here, when the WPS start button provided on the AP1 has been
pressed, the AP1 transmits the communication start response signal
having a PBC flag indicating that the WPS start button is pressed.
Meanwhile, the STA2 (i) determines that the AP1 which is the source
of the communication start response signal having the PBC flag is
the communication partner, and (ii) executes the step 2 shown in
FIG. 4 between the AP1.
[0087] In the step 2 shown in FIG. 4, a message complying with an
Extensible Authentication Protocol over LAN (EAPOL). is transmitted
and received between the AP1 and the STA2. Here, detailed
description on the overall EAPOL is omitted to focus on some part
of the EAPOL closely related to the present invention.
[0088] The device-information-exchange control unit 10 of the AP1
obtains device information of the STA2 (S102), by exchanging the
device information with the STA2, the device information being
required for distributing the connection information (S102). The
obtained device information is held for each of the STA2 to the
STA5 by the communication terminal management unit 9, as shown in
FIG. 13. Specifically, the STA2 (i) includes various information of
the STA2 into a device information transmission signal (M1 message)
and (ii) transmits the signal to the AP1. FIG. 5 and FIG. 6 show a
data structure of the device information transmission signal. It
goes without saying that the device information transmission signal
does not necessarily be the M1 message and may be a message
transmitted from the STA.
[0089] The device information transmission signal includes, for
example, a Universally Unique Identifier (uuid) which is uniquely
assigned to each device, and a device type (Primary Device Type).
The Primary Device Type is specified, for example, as shown in FIG.
6, by a combination of (i) a Category which includes "Computer",
"Displays", "Multimedia Devices", and so forth, and (ii) a Sub
Category resulting from dividing each Category into "Television",
"Personal Video Recorder (PVR)", and so forth.
[0090] Furthermore, in this embodiment, (i) a new item ("New Field"
in FIG. 5) may be added to the conventional device information
transmission signal, and (ii) information such as "category",
"supported frequency band", and "desired frequency band" may be set
to the new item. It is to be noted that such items are not
mandatory and may be omitted.
[0091] As specific examples of Category, "Voice", "Video",
"BestEffort", "Back Ground", and so forth are raised. To the
supported frequency band, information for specifying one or more
frequency bands (2.4 GHz band and 5 GHz band) with which the STA2
is capable of performing wireless communication is set. To the
desired frequency band, information for specifying a frequency band
(the 2.4 GHz band or the 5 GHz band) is set, where the frequency
band is desired for use in the wireless communication with the AP1
by the STA2.
[0092] After obtaining such device information of the STA2, the
device-information-exchange control unit 10 of the AP1 executes a
predetermined key exchange (S103) according to the WPS standard. A
key to be exchanged here is a temporal key for coding and decoding
the connection information distributed in S105, and an actual key
for coding and decoding the wireless signal is included in the
connection information.
[0093] When the predetermined key exchange is completed normally
(Yes in D103), the SSID issuance management unit 7 of the AP1
issues an SSID to the STA2 and registers the SSID with the
connection information management unit 13 (S104). It is to be noted
that the SSID issuance management unit 7 in the first embodiment
assigns a unique SSID to each of the STA2 to the STA5. Furthermore,
the assigned SSID and the associated device information of the STA2
obtained by the device-information-exchange control unit 10 are
held by the communication terminal management unit 9.
[0094] Subsequently, the connection information distribution unit
12 of the AP1 distributes, to the STA2, the connection information
for connecting to the AP1, along with the SSID assigned to the STA2
(S105). Specifically, the AP1 (i) includes the connection
information, including the SSID, into connection information
distribution signal (M8 message) and (ii) transmits the connection
information distribution signal to the STA2. This method allows to
assign a different SSID to each of the STA2 to the STA5.
[0095] Here, the AP1 (i) allocates a channel (operation frequency)
in the 5 GHz band or the 2.4 GHz band to the STA2 to the STA5 which
are the sources of the communication start request signal, and (ii)
distributes the connection information associated with the
allocated channel. Specifically, the AP1 allocates the channel
based on the supported frequency information (which is the
"supported frequency band", the "desired frequency band", the
"Primary Device Type", and the "category" described below) received
from each of the STA2 to the STA5. A process of allocating the
channel, to be performed by the AP1, is described in detail below,
with reference to FIG. 7A to FIG. 12.
[0096] As a first method of allocation, the AP1 is capable of
allocating the channel based on the "supported frequency band"
included in the device information transmission signal received by
each of the STA2 to the STA5. It is to be noted that the supported
frequency band is an item to which one or more frequency bands are
set, where the one or more frequency bands are the frequency bands
in which the wireless communication terminal is capable of
performing wireless communication. The wireless communication
terminal in this embodiment sets all the frequency bands the
wireless communication terminal supports as the supported frequency
bands.
[0097] For example, FIG. 7A shows an example of the supported
frequency band included in the device information transmission
signal received from the STA2 to the STA5. In FIG. 7A, "1"
indicates that the frequency band is supported, and "0" indicates
that the frequency band is not supported. Furthermore, a column
enclosed in a thick-frame shows a frequency band to which the
channel allocated to each of the wireless communication terminals
belongs.
[0098] As shown in FIG. 7A, the AP1 allocates the channel in the 5
GHz band to the STA2 and the STA3 which support both of the 2.4 GHz
band and the 5 GHz band. Furthermore, the AP1 allocates the channel
in the 5 GHz band to the STA4 which only supports the 5 GHz to
band. Furthermore, the AP1 allocates the channel in the 2.4 GHz
band to the STA5 which only supports the 2.4 GHz band. That is, in
the example shown in FIG. 7A, the AP1 allocates (i) the channel in
the 5 GHz band to the wireless communication terminal supporting
the 5 GHz band, and (ii) the channel in the 2.4 GHz band to the
wireless communication terminal not supporting the 5 GHz band.
[0099] Furthermore, as a second method of allocation, the AP1 is
capable of allocating the channel based on the "desired frequency
band" included in the device information transmission signal
received by each of the STA2 to the STA5. It is to be noted that
the desired frequency band is an item to which a frequency band is
set, where the frequency band is desired, by the STA, for use in
the wireless communication with the AP1. The wireless communication
terminal in this embodiment may set, as the desired frequency band,
(i) a predetermined frequency band or (ii) a frequency band which
has the best reception state (received power or the interference
state described later).
[0100] For example, FIG. 7B shows an example of the desired
frequency band included in the device information transmission
signal received from the STA2 to the STA5. In FIG. 7B, "1"
indicates that the wireless communication terminal desires to use
the frequency band. Furthermore, a column enclosed in a thick-frame
shows a frequency band to which the channel allocated to each of
the wireless communication terminals belongs.
[0101] As shown in FIG. 7B, the AP1 allocates the channel in the 5
GHz band to the STA2 to the STA4 which desire the 5 GHz band.
Meanwhile, the AP1 allocates the channel in the 2.4 GHz band to the
STA5 which desires the 2.4 GHz band. That is, in the example in
FIG. 7B, the AP1 allocates the channel of the frequency band
desired by the wireless communication terminal.
[0102] Furthermore, as a third method of allocation, the AP1 is
capable of allocating the channel based on the "Primary Device
Type" (a combination of the Category and the Sub category in FIG.
6) included in the device information transmission signal received
from each of the STA2 to the STA5. In this case, the AP1 needs to
hold a in conversion table as shown in FIG. 8A in advance. This
conversion table may be held in a fixed manner or in a manner that
can be changed by the user. The conversion table shown in FIG. 8A
holds (i) the Primary Device Type of a wireless communication
terminal and (ii) a frequency band of the channel to be allocated
to the wireless communication terminal having the Primary Device
Type, such that the Primary Device Type and the frequency band are
associated with each other.
[0103] As shown in FIG. 8B, the AP1 allocates the channel in the
2.4 GHz band to the STA2 having "Computer" as the Category and "PC"
as the Sub category. In the same manner, the AP1 (i) obtains the
frequency band associated with the Primary Device Type of the STA3
to the STA5 from the conversion table shown in FIG. 8A and (ii)
allocates the channel in the obtained frequency band to each of the
STA3 to the STA5.
[0104] Furthermore, as a fourth method of allocation, the AP1 is
capable of allocating the channel based on the "Category" included
in the device information transmission signal received by each of
the STA2 to the STA5. In this case, the AP1 needs to hold a
conversion table as shown in FIG. 9A in advance. The conversion
table shown in FIG. 9A holds (i) the Category of a wireless
communication terminal and (ii) the frequency band of the channel
to be allocated to the wireless communication terminal, such that
the Category and the frequency band are associated with each other.
This conversion table may be held in a fixed manner or in a manner
that can be changed by the user.
[0105] As shown in FIG. 9B, the AP1 allocates the channel in the
2.4 GHz band to the STA2 having "Best Effort" as the category. In
the same manner, the AP1 (i) obtains the frequency band associated
with the category of the STA3 to the STA5 from the conversion table
shown in FIG. 9A and (ii) allocates the channel in the obtained
frequency band to each of the STA3 to the STA5.
[0106] Furthermore, as a modification example of the first method
of allocation, the AP1 may obtain the supported frequency band of
each of the wireless communication terminals from the communication
start request signal. A method of obtaining the supported frequency
band of the STA2 to the STA5 from the communication start request
signal is described with reference to FIG. 10A and FIG. 10B.
[0107] As described above, the STA2 transmits the communication
start request signal to all of the channels in the frequency bands
which the STA2 supports. Furthermore, an identical MAC address
(MAC-A) is set in all of the communication start request signals
transmitted by the STA2. The same goes for the STA3 to the
STA5.
[0108] As shown in FIG. 10A and FIG. 10B, the AP1 determines that
the STA2 supports both of the 2.4 GHz band and the 5 GHz band, upon
receipt of the communication start request signal having the MAC-A
set as the MAC address in both of the 2.4 GHz band and the 5 GHz
band. The same goes for the STA3 and the STA4. Meanwhile, the AP1
determines that the STA5 supports only the 2.4 GHz band, upon
receipt of the communication start request signal having the MAC-D
set as the MAC address in the 2.4 GHz band only.
[0109] As described above, by knowing the supported frequency band
of each of the wireless communication terminal using the
communication start request signal, an advantageous effect is
achieved that there is no need to add a new item to the device
information transmission signal as described in the first method of
allocation.
[0110] Furthermore, in addition to the modification example of the
first method of allocation, the AP1 may allocate the channel by
taking magnitude of the received power of the communication start
request signal into consideration. It is to be noted that a
"received power (dBm)" indicates a value measurable by the wireless
communication interface 11 of the AP1, and includes, for example,
Receive Signal Strength Indication (RSSI).
[0111] Specifically, as shown in FIG. 11, the AP1 measures the
received power of the communication start request signal received
from each of the STA2 to STA5, in a channel in each frequency band
that the AP1 is operating. It is to be noted that the received
power needs to be independently measured for all of the
communication start request signals, because the RSSI fluctuates
according to a in positional relationship between the AP1 and each
of the wireless communication terminals. In FIG. 11, "1" indicates
that a communication start request signal is received in the
frequency band. Furthermore, a column enclosed in a thick-frame
shows the frequency band to which the channel allocated to each of
the wireles communication terminals belongs.
[0112] The AP1 allocates a channel in the frequency band having the
highest received power, to the wireless communication terminal
which supports frequency bands. That is, as shown in FIG. 11, the
AP1 allocates a channel in the 5 GHz band having the higher
received power, to the STA2 which supports both of the 2.4 GHz band
and the 5 GHz band. In the same manner, the AP1 allocates a channel
in the 2.4 GHz band having the higher received power, to the STA3
which supports both of the 2.4 GHz band and the 5 GHz band.
Meanwhile, the AP1 allocates, to the STA4 and the STA5 which
support only one of the 2.4 GHz band and the 5 GHz band, the
channel in the supported frequency band, regardless of the
magnitude of the received power.
[0113] As described above, by allocating the channel in the
frequency band having the higher received power, out of the
supported frequency bands, it is possible to select the appropriate
frequency band depending on a communication environment. It is to
be noted that an example which is a combination of (i) the
modification example of the first method of allocation and (ii) the
received power has been described here, however, without being
limited to this example, the same effect may be produced by
combining the received power with the first method of allocation,
the third method of allocation, or the fourth method of
allocation.
[0114] Furthermore, in addition to the modification example of the
first method of allocation, the AP1 may allocate a channel by
taking the interference state of each of the frequency bands into
consideration. It is to be noted that the "interference state"
indicates a value measurable by the wireless communication
interface 11 of the AP1, and is measurable, for example, by Packet
Error Ratio (PER) of a signal (packet) received in a channel in
each frequency band that the AP1 is operating. Furthermore, the PER
may be calculated based on, for example, a glitch, a Cyclic
Redundancy Check (CRC) of a Physical Layer Convergence Protocol
(PLCP) header, or the like.
[0115] Specifically, as shown in FIG. 12, the AP1 receives the
communication start request signal from each of the STA2 to the
STA5 and measures the interference state of each of the frequency
bands. That is, the AP1 determines that the interference state is
bad (in a state where there are frequent occurrences of
interference and indicated as "High" in FIG. 12), when the PER of
the packet received in the 2.4 GHz band is equal to or more than a
predetermined threshold. Meanwhile, the AP1 determines that the
interference state is good (in a state where there are a few
occurrences of interference and indicated as "Low" in FIG. 12),
when the PER of a packet received in the 5 GHz band is below the
predetermined threshold. It is to be noted that it is sufficient to
measure the interference state based on a given signal transmitted
in each of the frequency bands, which is different from the case
with the received power described above. Furthermore, the threshold
for each of the frequency bands may be identical or may be set
individually for each of the frequency bands.
[0116] The AP1 allocates the channel in the frequency band with the
interference state lower than the threshold, to the wireless
communication terminal which supports frequency bands. That is, as
shown in FIG. 12, the AP1 allocates the channel in the 5 GHz band
with the interference state lower than the threshold, to the STA2
and the STA3 which support both of the 2.4 GHz band and the 5 GHz
band. Meanwhile, the AP1 allocates, to the STA4 and the STA5 which
support only one of the 2.4 GHz band and the 5 GHz band, the
channel in the supported frequency band, regardless of the
interference state.
[0117] As described above, by allocating the channel in the
frequency band with the lower interference state, it is possible to
select the channel in the appropriate frequency band depending on
the communication environment. It is to be noted that an example
which is a combination of (i) the modification example of the first
method of allocation and the (ii) interference state has been
described here, however, without being limited to this example, the
same effect may be produced by combining the interference state
with the first method of allocation, the third method of
allocation, or the fourth method of allocation. Moreover, the
received power and the interference state may be combined.
[0118] When all of the STA2 to the STA5 shown in FIG. 1 are
connected to the AP1, the communication terminal information
managed by the is communication terminal management unit 9 of the
AP1 is, for example, as shown in FIG. 13. It is to be noted that
the "MAC" shown in FIG. 13 is information for identifying each of
the STA2 to the STA5 and, for example, a MAC address may be used.
The "Primary Device Type" is information included in the device
information obtained from the STA2 to the STA5 (the Sub Category in
FIG. 6 in this example), and indicates a type (Television, PVR, PC,
etc.) of each of the STA2 to the STA5. The "Category" indicates the
real-timeliness (Video, BestEffort, etc.) required for the wireless
communication in an application executed by each of the STA2 to the
STA5. The "SSID" indicates the SSID issued by the SSID issuance
management unit 7 to each of the STA2 to the STA5. The "Band"
indicates the frequency band (the 5 GHz band or the 2.4 GHz band)
currently being used for the wireless communication with each of
the STA2 to the STA5. The "Channel" indicates the channel currently
being used for the wireless communication with each of the STA2 to
the STA5. In FIG. 13, "36" indicates the channel 36 and "1"
indicates the channel 1.
[0119] The "5 GHzFlg" indicates whether or not each of the STA2 to
the STA5 has experienced the wireless communication with the AP1 in
the 5 GHz band (experienced:1 and unexperienced:0). The "OldBand"
indicates the frequency band that has been used immediately before
the frequency band indicated in the "Band". It is to be noted that
FIG. 13 shows a state immediately after the STA2 to the STA5 are
connected with the AP1, thus the "OldBand" is not registered.
[0120] As shown in FIG. 13, in the communication terminal
management unit 9, the following are registered as the
communication terminal information of the STA2: "MAC-A" as the MAC;
"Television" as the Primary Device Type; "Video" as the Category;
"SSID-A" as the SSID; "5 GHz" as the Band; "36" as the Channel; "1"
as the 5 GHzFlg; and "-(unregistered)" as the "Oldband".
[0121] Furthermore, in the communication terminal management unit
9, the following are registered as the communication terminal
information of the STA3: "MAC-B" as the MAC; "PVR" as the Primary
Device Type; "Video" as the Category; "SSID-B" as the SSID; "5GHz"
as the Band; "36" as the Channel; "1" as the 5 GHzFlg, and "-" as
the "Oldband".
[0122] Furthermore, in the communication terminal management unit
9, the following are registered as the communication terminal
information of the STA4: "MAC-C" as the MAC; "PC" as the Primary
Device Type; "BestEffort" as the Category; "SSID-C" as the SSID; "5
GHz" as the Band; "36" as the Channel; "1" as the 5 GHzFlg; and "-"
as the "Oldband".
[0123] Furthermore, in the communication terminal management unit
9, the following are registered as the communication terminal
information of the STA5: "MAC-D" as the MAC; "PVR" as the Primary
Device Type; "Video" as the Category; "SSID-D" as the SSID; "2.4
GHz" as the Band; "1" as the Channel; "0" as the 5 GHzFlg; and "-"
as the "Oldband". It is to be noted that the operation frequency of
the STA5 is the 2.4 GHz band, since the STA5 does not support the 5
GHz band.
[0124] It is to be noted that the AP1 determines the
real-timeliness required for the wireless communication in the
application executed by each of the STA2 to the STA5, by referring
to the Primary Device Type or the Category shown in FIG. 13. It is
to be noted that both of the Primary Device Type and the Category
are information which indicate a type of the wireless communication
terminal.
[0125] For example, the AP1 determines that the application to be
executed by the STA2, the STA3, and the STA5, all of which are
having the "Television" or the "PVR" as the device information,
requires the higher real-timeliness in the wireless communication
than the STA4 that belongs to "PC". For example, in the conversion
table shown in FIG. 8A, it is possible for the AP1 to determine
that the application executed by the wireless communication
terminal having the device information associated with the 5 GHz
band requires the higher real-timeliness in the wireless
communication than the application executed by the wireless
communication terminal having the device information associated
with the 2.4 GHz band.
[0126] Furthermore, the AP1 determines that the application
executed by the STA2, the STA3 and the STA5, all of which belong to
the "Video" category requires the higher real-timeliness in the
wireless communication than the application executed by the STA4
which belongs to the "BestEffort" category. For example, in the
conversion table shown in FIG. 9A, it is possible for the AP1 to
determine that the application to be executed by the wireless
communication terminal having the category associated with the 5
GHz band requires the higher real-timeliness in the wireless
communication than the application to be executed by the wireless
communication terminal having the category associated with the 2.4
GHz band.
[0127] It goes without saying that the Primary Device Type and the
Category are not limited to the above examples and may be any
identification information. Moreover, regarding the Category, the
AP1 may uniquely categorize the wireless communication terminals
based on the Primary Device Type or the like from the STA2. For
example, when the Primary Device Type (the Sub Category in FIG. 6)
obtained from the STA2 is the "Television" or the "PVR", in which
the application requiring real-timeliness is often executed, the
AP1 may determine that the Category of the STA2 is "Video". The
category here is according to an access category (Voice, Video,
BestEffort, and BackGround) stipulated by WiFi, however, it goes
without saying that other categories may be used.
[0128] Next, an operation of the AP1 when the operation frequency
of each of the STA2 to the STA5 is moved is described using the
flowchart in FIG. 14. It is assumed here that, for example, the
STA2 starts VoD viewing from the Internet.
[0129] The communication-terminal-status determination unit 6 of
the AP1 always supervises, as an object to be detected, the
communication traffic volume of the STA2, the STA3 and the STA5,
all of which belong to the Video category, out of the STA2 to the
STA5 managed by the communication terminal management unit 9.
Specifically, the communication-terminal-status determination unit
6 in detects the communication traffic volume of a frame having a
source MAC address or a destination MAC address to which one of the
"MAC-A", "MAC-B", or "MAC-C" is set, out of frames received by the
AP1.
[0130] When the STA2 starts the VoD, the
communication-terminal-status determination unit 6 of the AP1
detects, for example, that the STA2 is performing communication at
a velocity greater than 5 Mbps (the threshold) (S201). Here, the
following steps are described based on an assumption that the STA
has started the communication greater than 5 Mbps. It is to be
noted that to perform communication with a velocity (or a
communication traffic volume) greater than the threshold is an
example of the communication status to satisfy the predetermined
condition.
[0131] It is to be noted that although the threshold has been set
to 5 Mbps in S201, a specific value is not limited to this value
and an appropriate value may be set depending on such as a type of
an application to be executed. Furthermore, it goes without saying
that this threshold may be the velocity or the communication
traffic volume, as long as the threshold allows the
communication-terminal-status determination unit 6 to determine
that the STA2 is executing the application.
[0132] Next, the communication-terminal-status determination unit 6
determines whether or not the communication is performed in the 5
GHz band (S202). When the communication is performed in the 5 GHz
band (Yes in S202), the communication-terminal-status determination
unit 6 of the AP1 instructs the frequency control unit 8 to move
the STA3 and the STA4 to which the 5 GHz band are allocated other
than the STA2, out of the STA3 to the STA5, to the 2.4 GHz band,
based on the communication terminal information held by the
communication terminal management unit 9. More specifically, the
communication-terminal-status determination unit 6 causes the
frequency control unit 8 to move the operation frequencies of the
STA3 and the STA4 to which different SSIDs from the SSID assigned
to the STA2 (SSID-A) are assigned, out of the STA2 to the STA4
performing the wireless communication using the 5 GHz band, to the
2.4 GHz band.
[0133] It is to be noted that the new frequency band in which the
STA3 and the STA4 operate is designated here, however, the channel
may be determined arbitrarily. For example, a vacant channel or a
channel being used by the STA5 that is already in connection may
also be designated.
[0134] Then, the communication terminal information managed by the
communication terminal management unit 9 is updated as shown in
FIG. 15. In the case of the first embodiment, specifically, the
Band in the communication terminal information of (i) the STA3 to
which the SSID-B, different from the SSID-A, is assigned and is
operating in the 5 GHz band and (ii) the STA4 to which the SSID-C,
different from the SSID-A, is assigned and is operating in the 5
GHz band, are changed from the 5 GHz band to the 2.4 GHz band. In
this case, the STA3 and the STA4 are allocated with the same
channel as the STA5 to use in the 2.4 GHz band, and thus the
Channel in the communication terminal information is to be changed
from "36" to "1".
[0135] When referring to FIG. 15, regarding the communication
terminal information of the STA2 managed by the communication
terminal management unit 9, the OldBand is updated from "-" to "5
GHz". Furthermore, regarding the communication terminal information
of the STA3 managed by the communication terminal management unit
9, the Band is updated from "5 GHz" to "2.4 GHz", the Channel is
updated from "36" to "1", and the OldBand is updated from "-" to "5
GHz". Furthermore, regarding the communication terminal information
of the STA4 managed by the communication terminal management unit
9, the Band is updated from "5 GHz" to "2.4 GHz", the Channel is
updated from "36" to "1", and the OldBand is updated from "-" to "5
GHz". Moreover, regarding the communication terminal information of
the STA5 managed by the communication terminal management unit 9,
the OldBand is updated from "-" to "2.4 GHz".
[0136] When the value of the Band associated with the SSID-B and
the value of the Band associated with the SSID-C the SSID-C, held
by the communication terminal management unit 9, are changed, the
wireless communication interface 11 transmits the beacon signal
including the SSID-B and the beacon signal including the SSID-C
using the new frequency band (that is, the 2.4 GHz band).
[0137] Meanwhile, after this, the STA3 becomes unable to receive
the beacon signal including the SSID assigned to the STA3, and the
STA4 becomes unable to receive the beacon signal including the SSID
assigned to the STA4, even when the beacon signals are supervised
in the 5 GHz band. Therefore, the STA3 and the STA4 start the
roaming.
[0138] By the roaming, the STA3 becomes able to detect the beacon
signal including the SSID of the STA3, and the STA4 becomes able to
detect the beacon signal including the SSID of the STA4, in the 2.4
GHz band, and thus the STA3 and the STA4 are reconnected to the AP1
in the 2.4 GHz band.
[0139] With the above procedure performed by the AP1, when the STA2
executes the application requiring real-timeliness, the STA3 and
the STA4 that are not executing the applications or the STA5 that
is executing the application not requiring real-timeliness are
moved to the 2.4 GHz band. As a result, the STA2 is allowed to
execute the application without the band being overwhelmed.
[0140] Next, in order to describe the operation after S204, a case
is assumed that the STA3 that has been moved to the 2.4 GHz band
has executed the application requiring real-timeliness, as shown in
FIG. 15.
[0141] The communication-terminal-status determination unit 6
determines, when detecting that the STA3 in the Video category is
performing wireless communication at the velocity greater than 5 M
bps (Yes in S201), whether or not the STA3 is operating in the 5
GHz band and whether or not the STA3 is performing the wireless
communication using the 2.4 GHz band (S202). In this example, the
STA3 is performing the wireless communication using the 2.4 GHz
band (Yes in S202).
[0142] Next, the frequency control unit 8 of the AP1 checks the 5
GHzFlg of the STA3 and checks whether or not there is a history of
the STA3 connected to the AP1 in the 5 GHz band (S204). The
frequency control unit 8 determines that the STA3 has a function to
connect to the 5 GHz band (Yes in S204), because the STA3 has the
history of connection to the AP1 in the 5 GHz band (has the Flg
indicating 1). in The frequency control unit 8 then changes the
operation frequency allocated to the STA3 from the 2.4 GHz band to
the 5 GHz band (S205).
[0143] Next, the frequency control unit 8 of the AP1 moves the
STA2, which is performing the wireless communication using the 5
GHz band and to which the SSID different from the SSID assigned to
the STA3 (SSID-B) is assigned, to the 2.4 GHz band (S203). The
specific content of the process is omitted since it is already
described.
[0144] Here, the frequency control unit 8 may further (i) cause the
communication-terminal-status determination unit 6 to determine the
communication status of the STA2, and (ii) determine whether or not
to move the STA2 from the 5 GHz band to the 2.4 GHz band. For
example, the frequency control unit 8 may determine not to move the
STA2 to the 2.4 GHz band, when the STA2 is continuously executing
the application requiring real-timeliness (that is, the STA2 is
performing the wireless communication at the velocity greater than
5 Mbps).
[0145] The above structure allows to prevent processes of other
wireless communication terminals, each of which is executing the
application requiring real-timeliness, from being interrupted due
to the start of the execution of the application requiring
real-timeliness by a single wireless communication terminal.
[0146] Meanwhile, when there is no history of the STA3 connected in
the 5 GHz band (No in S204), the frequency control unit 8
determines that the STA3 does not have the function to connect in
the 5 GHz band and does not move the SSID. Alternatively, the
frequency control unit 8 may skip the process of S204 and try to
communicate in the 5 GHz band regardless of the value of the 5
GHzFlg. This allows the frequency control unit 8 to move, to the 5
GHz band, the wireless communication terminal which has the
function to perform the wireless communication in the 5 GHz band
but has no experience in actual communication in the 5 GHz
band.
[0147] Furthermore, in the first embodiment, when the
communication-terminal-status determination unit 6 detects that the
packet communication traffic volume of the STA2 is changed from the
status greater than the threshold to the status equal to or less
than the threshold, the frequency control unit 8 may move the
operation frequencies of the SSID-B and the SSID-C, for which the
frequency bands have been moved, back to the 5 GHz band.
[0148] The above procedure allows even the STA3 and the STA4, for
which the frequency bands have been moved to the 2.4 GHz band, to
be moved back to the 5 GHz band when the STA3 and the STA4 execute
the application requiring real-timeliness. Therefore, the
application can be executed with less effect of the interference.
Furthermore, the above process can be achieved by implementing this
function to only the AP1 side, because the roaming function of the
STA2 to the STA4 is used. This allows an easy relocation from an
existing apparatus to the AP1.
Second Embodiment
[0149] Next, the second embodiment is described. The difference
between the first embodiment and the second embodiment is in the
way the AP1 assigns the SSID. Specifically, it is different that,
in the first embodiment, the SSID issuance control unit 7 assigns
the unique SSID to each of the STA2 to the STA5, while, in the
second embodiment, the SSID issuance control unit 7 assigns a
unique SSID to each of the categories to which each of the STA2 to
the STA5 belongs. The description on commonalities with the first
embodiment is omitted in the description below to focus on
differences.
[0150] The AP1 starts the WPS and so forth with the STA2 (S101),
and obtains the device information of the STA2 (S102), in the same
manner as the first embodiment. The device information includes,
for example, the uuid, the Primary Device Type, or the Category
which are assigned uniquely to each of the STA2 to the STA5.
[0151] For example, as examples of the Primary Device Type,
"Television", "PVR", and "PC" are raised. Specific examples of the
category are "Video", "BestEffort", or the like. It goes without
saying that any identification information may be used in the
Primary Device Type and the Category.
[0152] Moreover, regarding the Category, the AP1 may uniquely
categorize the wireless communication terminals based on the
information from the STA2. For example, when the Primary Device
Type of the STA2 is the "Television" or the "PVR", in which the
application requiring real-timeliness is often executed, the AP1
may determine that the category of the STA2 is the "Video". It goes
without saying that the category here is according to an access
category (Voice, Video, BestEffort, and BackGround) stipulated by
WiFi, however, other category may be used.
[0153] After obtaining such device information of the STA2, a key
exchange according to the WPS standard is executed (S103). When the
predetermined key exchange is completed, the SSID issuance
management unit 7 of the AP1 issues an SSID different for each of
the categories to the STA2, and registers the SSID with the
connection information management unit 13 (S104). Then, the SSID
issuance management unit 7 distributes the connection information
to the STA2, the connection information being for connecting with
the AP1 (5105). This method allows to assign a different SSID to
each of the categories.
[0154] Specifically, it is different that the issuance control unit
7 assigns, in the first embodiment, the SSID unique to each of the
STA2 to the STA5, while, the SSID unique to each of the categories
to which each of the STA2 to the STA5 belongs, in the second
embodiment. Other processes shown in FIG. 3 (S101 to S103 and S105)
are common with the first embodiment.
[0155] When all of the STA2 to the STA5 shown in FIG. 1 are
connected to the AP1, the communication terminal information
managed by the communication terminal management unit 9 of the AP1
is as shown in FIG. 16.
[0156] As shown in FIG. 16, in the communication terminal
management unit 9, the following are registered as the
communication terminal information of the STA2: "MAC-A" as the MAC;
"Television" as the Primary Device Type; "Video" as the Category;
"SSID-A" as the SSID; "5 GHz" as the Band; "1" as the 5 GHzFlg; and
"-" as the Oldband.
[0157] Furthermore, in the communication terminal management unit
9, the following are registered as the communication terminal
information of the STA3: "MAC-B" as the MAC, "PVR" as the Primary
Device Type, "Video" as the Category, "SSID-A" as the SSID, "5 GHz"
as the Band, "36" as the Channel, "1" as the 5 GHzFlg, and "-" as
the Oldband.
[0158] Furthermore, in the communication terminal management unit
9, the following are registered as the communication terminal
information of the STA4: "MAC-C" as the MAC, "PC" as the Primary
Device Type, "BestEffort" as. the Category, "SSID-C" as the SSID,
"5 GHz" as the Band, "36" as the Channel, "1" as the 5 GHzFlg, and
"-" as the Oldband.
[0159] Moreover, in the communication terminal management unit 9,
the following are registered as the communication terminal
information of the STA5: "MAC-D" as the MAC, "PVR" as the Primary
Device Type, "Video" as the Category, "SSID-D" as the SSW, "2.4
GHz" as the Band, "1" as the Channel, "0" as the 5 GHzFlg, and "-"
as the Oldband. It is to be noted that the operation frequency
(Band) of the STA5 is the 2.4 GHz band, because the STA5 does not
support the 5 GHz band. Therefore, the Category of the STA5 is the
"Video", however, the STA5 is assigned with not "SSID-A" which is
the same as the STA2 and the STA3 but "SSID-B".
[0160] Next, an operation of the AP1 when the operation frequency
is moved is described using the flowchart in FIG. 17. It is assumed
here that, for example, the STA2 starts VoD viewing from the
Internet.
[0161] The communication-terminal-status determination unit 6 of
the AP1 always supervises, as the object to be detected, the
communication traffic volume of the STA2, the STA3 and the STA5
which belong to the Video category, out of the STA2 to the STA5
managed by the communication terminal management unit 9 (S301).
[0162] When the STA2 starts the VoD, the
communication-terminal-status determination unit 6 of the AP1
detects, for example, that the STA2 is performing communication at
a velocity greater than 5 Mbps (the threshold) (Yes in S301). It
goes without saying that this threshold may be the velocity or the
communication traffic volume, as long as it allows the
communication-terminal-status determination unit 6 to determine
that the STA2 is executing the application.
[0163] Next, the communication-terminal-status determination unit 6
determines whether or not the communication is performed in the 5
GHz band (S302). When the communication is performed in the 5 GHz
band (Yes in S302), the communication-terminal-status determination
unit 6 of the AP1 instructs the frequency control unit 8 to switch
the frequency band to use of the STA4, which belongs to the
category different from the STA2, from the 5 GHz band to the 2.4
GHz band, based on the communication terminal information of the
communication terminal management unit 9. It is to be noted that
the new frequency band is designated here, however, the channel may
be determined arbitrarily. For example, a vacant channel or a
channel being used by the STA5 that is already in connection may be
designated.
[0164] In the second embodiment, specifically, the SSID-C which is
assigned to the STA4 and is operating in the 5 GHz band is changed
to operate in the 2.4 GHz band. That is, the Band associated with
the SSID-C of the STA4 is changed from the "5 GHz band" to the "2.4
GHz band". Accordingly, the communication terminal information
managed by the communication terminal management unit 9 is updated
as shown in FIG. 18.
[0165] When referring to FIG. 18, regarding the communication
terminal information of the STA2 managed by the communication
terminal management unit 9, the Oldband is updated from "-" to "5
GHz band". Furthermore, regarding the communication terminal
information of the STA3 managed by the communication terminal
management unit 9, the OldBand is updated from "-" to "5 GHz band".
Furthermore, regarding the communication terminal information of
the STA4 managed by the communication terminal management unit 9,
the Band is updated from the "5 GHz band" to the "2.4 GHz band",
the Channel is updated from "36" to "1", and the OldBand is updated
from "-" to "5 GHz band". Moreover, regarding the communication
terminal information of the STA5 managed by the communication
terminal management unit 9, the OldBand is updated from "-" to the
"2.4 GHz band".
[0166] After this, the STA4 starts the roaming because the STA4 is
no longer capable of receiving the beacon signal including STA-C.
Performing the roaming enables the STA4 to detect the beacon signal
including the SSID-C in the 2.4 GHz band, and thus the STA4 is
reconnected to the AP1 in the 2.4 GHz band.
[0167] Furthermore, in the second embodiment, when the
communication-terminal-status determination unit 6 of the AP1 does
not detect a certain amount of packet communication traffic volume
any more, the frequency control unit 8 may move the operation
frequency of the SSID-C, for which the operation frequency has been
moved from the "2.4 GHz band", back to the "5 GHz band".
[0168] The above procedure taken by the AP1 allows the STA2, the
STA3, and the STA5, each of which executes the application
requiring real-timeliness, to be divided by categories and thus
enables a compartmentalization of the frequency bands of the
wireless LANs. As a result, an artifact due to the overwhelmed band
or a decrease in the velocity is mitigated. Moreover, the
difficulty in introducing the roaming function of the STA2 to the
STA5 is lowered.
Third Embodiment
[0169] The difference between the third embodiment and the first
embodiment is in a specific procedure of determining whether or not
the STA2, the STA3 and the STA5 has executed the application
requiring real-timeliness. Specifically, it is different that the
communication-terminal-status determination unit 6 determines, in
the first embodiment, based on whether or not the volume of the
wireless communication is greater than the threshold, while, in the
second embodiment, based on whether or not priority of
communication data is greater than the threshold. It is to be noted
that to perform communication with priority of communication data
greater than the threshold is an example of the communication
status to satisfy the predetermined condition. The description on
commonalities with the first embodiment is omitted in the
description below to focus on differences.
[0170] In the third embodiment, a specific process is described in
detail, where the process is for determining, by the
communication-terminal-status determination unit 6, that the STA2
has executed the application requiring real-timeliness. Other
process operations by the AP1 are common with the first
embodiment.
[0171] As shown in FIG. 20, the communication-terminal-status
determination unit 6 of the AP1 always supervises, as the object to
be detected, the priority of the STA2, STA3 and the STA5 which
belong to the Video category, out of the STA2 to the STA5 managed
by the communication terminal management unit 9.
[0172] An example of the object to be detected is (i) a Type of
Service (ToS) field or (ii) a DSCP field, shown in FIG. 19, each of
which indicates the priority of the IP packet. These are fields
which describe the priority of the IP packet, and the ToS field,
for example, describes eight levels of priority. The priority of a
Video stream, stipulated by WiFi and so forth, is described as
5.
[0173] When the STA2 starts the VoD, the priority is added to a ToS
field of an IP header of a packet, where the packet is set with an
IP address of the STA2 as an destination address. The
communication-terminal-status determination unit 6 detects whether
or not the priority is equal to or more than a certain stipulation
(for example, equal to or more than 5) (S401). Regarding the
stipulation for the priority, it goes without saying that the
priority is not necessarily be equal to or more than 5, as long as
it is complying with a system or a standard. Furthermore, it goes
without saying that it is sufficient when it allows the
communication-terminal-status determination unit 6 to determine
that the STA2 is executing the application.
[0174] Then, the frequency control unit 8 performs the same process
as in the first embodiment to change the association between the
SSID and the Band in the communication terminal management unit 9,
to (i) cause the STA2, which has executed the application requiring
high real-timeliness, to operate in the 5 GHz band, and (ii) cause
the STA3 to the STA5, other than the STA2, to operate in the 2.4
GHz band.
[0175] Furthermore, in the third embodiment, when the
communication-terminal-status determination unit 6 does not detect
the packet of the STA2 added with the priority for a certain
period, the frequency control unit 8 may move the operation
frequencies of the SSID-B and the SSID-C, for which the operation
frequencies have been moved, from the "2.4 GHz band" back to the "5
GHz band".
Fourth Embodiment
[0176] The difference between the fourth embodiment and the second
embodiment is in a specific procedure of determining whether or not
the STA2, the STA3 and the STA5, in the Video category, have
executed the application requiring real-timeliness. Specifically,
it is different that the communication-terminal-status
determination unit 6 determines, in the second embodiment, based on
whether or not the volume of the wireless communication is greater
than the threshold, while, in the fourth embodiment, based on
whether or not the priority of the communication data is greater
than the threshold. The description on commonalities with the
second embodiment is omitted in the description below to focus on
differences.
[0177] In the fourth embodiment, a specific process is described in
detail, where the process is for determining, by the
communication-terminal-status determination unit 6, that the STA2
has executed the application requiring real-timeliness. Other
process operations by the AP1 are common with the second
embodiment.
[0178] The communication-terminal-status determination unit 6 of
the AP1 always supervises, as the object to be detected, the
priority of communication packets of STA2, the STA3 and the STA5
which belong to the Video category, out of the STA2 to the STA5
managed by the communication terminal management unit 9.
[0179] An example of the object to be detected is 1) a Type of
Service (ToS) field or 2) a DSCP field, shown in FIG. 19, each of
which indicates the priority of the IP packet. These are fields
which describe the priority of the IP packet, and the ToS field,
for example, describes eight levels of priority. The priority of
the Video stream, stipulated by WiFi and so forth, is described as
5.
[0180] When the STA2 starts the VoD, the priority is added to the
ToS field of the IP header of the packet, where the packet is set
with the IP address of the STA2 as the destination address. The
communication-terminal-status determination unit 6 detects whether
or not the priority is equal to or more than a certain stipulation
(for example, equal to or more than 5) (S401). Regarding the
stipulation for the priority, it goes without saying that the
priority is not necessarily be equal to or more than 5, as long as
it is complying with a system or a standard. It goes without saying
that it is sufficient when it allows the
communication-terminal-status determination unit 6 to determine
that the STA2 is executing the application.
[0181] Then, the frequency control unit 8 performs the same process
as in the first embodiment to changes the association between the
SSID and the Band in the communication terminal management unit 9,
to (i) cause the STA2 that has executed the application requiring
high real-timeliness and the STA3 that belongs to the same category
as the STA2, to operate in the 5 GHz band, and (ii) cause the STA4
and the STA5, other than the STA2 and the STA3, to operate in the
2.4 GHz band.
[0182] Furthermore, in the fourth embodiment, when the
communication-terminal-status determination unit 6 does not detect
the packet of the STA2 added with the priority for a certain
period, the frequency control unit 8 may move the operation
frequency of the SSID-C, for which the operation frequency has been
moved, from the "2.4 GHz band" back to the "5 GHz band".
Fifth Embodiment
[0183] Next, the fifth embodiment is described. First, the
structure of the wireless communication terminal (STA) 2 is
described using FIG. 22. The STA2 in the fifth embodiment includes
a wireless communication interface 14, an application control unit
15, an application determination unit 16, an application
information notification unit 17, a device-information-exchange
control unit 18, and a connection information management unit
19.
[0184] The wireless communication interface 14 is an interface for
transmitting and receiving a wireless signal between the AP1. That
is, the wireless communication interface 14 transmits, as the
wireless signal, the data generated by the application information
notification unit 17, the device-information-exchange control unit
18, and so forth, to the AP1. Furthermore, the wireless
communication interface 14 generates data from the wireless signal
received from the AP1, and notifies the generated data to the
device-information-exchange control unit 18, or the like. Moreover,
the wireless communication interface 11 receives the beacon signal
transmitted from the AP1 in a predetermined time interval.
[0185] The application control unit 15 executes an application
requiring the wireless communication between the AP1. An example of
such an application is an application which performs streaming
reproduction of an image data from a content server and so forth.
The application determination unit 16 determines the
real-timeliness in the wireless communication required for the
application to be executed by the application control unit 15. The
application information notification unit 17 notifies, to the AP1,
the result of determination by the application determination unit
16. Specifically, the application information notification unit 17
transmits the application execution notification to the AP1, when
the application requiring real-timeliness in the wireless
communication has been started. Meanwhile, the application
information notification unit 17 transmits the application
completion notification to the AP1, when the execution of the
application which has been executed by the application control unit
15 is completed.
[0186] The device-information-exchange control unit 18 exchanges
the device information between the AP1. That is, the
device-information-exchange control unit 18 (i) transmits the
device information of the STA2 to the AP1 and (ii) obtains the
device information of the AP1. The connection information
management unit 19 holds information (key information, etc.)
required by the wireless communication terminal for performing
wireless communication with the AP1.
[0187] It is to be noted that, after receiving the application
execution notification from the STA2, the AP1 uses (i) the 5 GHz
band for the wireless communication with the STA2 and (ii) the 2.4
GHz band for the wireless communication with other STAs, the STA3
to the STA5, each of which is assigned with the SSID different from
the STA2. Meanwhile, after receiving the application completion
notification from the STA2, the AP1 returns the frequency band of
the STA that has had the frequency band switched according to the
application execution notification back to the frequency band used
prior to the switching, out of the STA3 to the STA5.
[0188] Next, the operation of the STA2 according to the fifth
embodiment is described, using the flowchart in FIG. 23. In the
fifth embodiment, it is assumed that the STA2 has executed the VoD.
Furthermore, the state of the STA2 connected with the AP1 is the
same as in the first embodiment, and the communication terminal
information shown in FIG. 13 is held by the communication terminal
management unit 9 of the AP1.
[0189] The application determination unit 16 of the STA2 determines
whether or not the STA2 is executing the application requiring high
real-timeliness in the wireless communication (for example, a video
viewing using the VoD or DLNA).
[0190] When the application determination unit 16 determines that
the high real-timeliness is required (Yes in S601), the application
information notification unit 17 transmits the application
execution notification to the AP1 (S602). It is to be noted that
the way of notification is not limited. It goes without saying
that, for example, the application execution notification may be
included in an Information Elements (IE) of a MAC frame in the
wireless LAN, or may be a packet in an IP layer. It is sufficient
when it is notified to the AP1 that the application has been
executed.
[0191] Next, the operation of the AP1 after receiving the
application execution notification from the STA2 is described,
using the flowchart in FIG. 24.
[0192] When the application execution notification is received from
the STA2 (Yes in S701), the communication-terminal-status
determination unit 6 determines whether or not the communication is
performed in the 5 GHz band (S702).
[0193] When the communication is performed in the 5 GHz band (Yes
in S702), the communication-terminal-status determination unit 6 of
the AP1 instructs the frequency control unit 8 to move the
frequency bands of the STA3 and the STA4, which belong to the
category to different from the STA2, from the "5 GHz band" to the
"2.4 GHz band", based on the communication terminal information in
the communication terminal management unit 9. It is to be noted
that the frequency band is designated here, however, the channel
may be determined arbitrarily. For example, a vacant channel or a
channel being used by the STA5 that is already in connection may be
designated.
[0194] In the case of the fifth embodiment, specifically, regarding
the communication terminal information of the STA3 and the STA4,
each of which is currently performing wireless communication using
the 5 GHz band and assigned with the SSID different from the STA2,
the Band associated with the SSID-B and the Band associated with
the SSID-C are switched from the "5 GHz band" to the "2.4 GHz
band".
[0195] When the Band associated with the SSID-B and the Band
associated with the SSID-C are changed, the STA3 and the STA4 start
the roaming, because the STA3 becomes unable to receive the beacon
signal including the SSID of the STA3 and the STA4 becomes unable
to receive the beacon signal including the SSID of the STA4, in the
5 GHz band. By performing the roaming, the STA3 becomes able to
detect the beacon signal including the SSID of the STA3 in the 2.4
GHz band, and the STA4 becomes able to detect the beacon signal
including the SSID of the STA4 in the 2.4 GHz band, and thus the
STA3 and the STA4 are reconnected to the AP1 in the 2.4 GHz
band.
[0196] Next, in order to describe the operation after S204, a case
is assumed that the STA3, which has been moved to the 2.4 GHz band,
has executed the application requiring the real-timeliness.
[0197] The communication-terminal-status determination unit 6
receives the application execution notification from the STA3
(S701). The communication-terminal-status determination unit 6
determines that the communication is performed in the 2.4 GHz band
in S702 (No in S702).
[0198] Next, the communication-terminal-status determination unit 6
checks the 5 GHzFlg of the STA3 and checks whether or not the STA3
is connected in the 5 GHz band. Since the STA3 has the history of
connection in the 5 GHz band (has the Flg indicating 1), the
communication-terminal-status determination unit 6 determines that
the STA3 has the function to connect in the 5 GHz band (Yes in
S704), and the frequency control unit 8 changes the operation
frequency from the "2.4 GHz band" to the "5 GHz band" (S705). When
the STA3 has no history of connection in the 5GHz band, the
communication-terminal-status determination unit 6 determines that
the STA3 does not have the function to connect in the 5 GHz band
(No in S704), and the frequency control unit 8 does not change the
operation frequency.
[0199] Furthermore, the fifth embodiment is described based on the
first embodiment, however, the operations after receiving the
application execution notification from the STA2 may be replaced
with the operations in the second embodiment.
[0200] Furthermore, in the fifth embodiment, when the execution of
the application is completed, the STA2 transmits the application
completion notification to the AP1. After receiving the application
completion notification, the AP1 may return the operation
frequencies of the STA3 and the STA4 that have had the frequency
bands switched upon receiving the preceding application execution
notification to the "5 GHz band" from the "2.4 GHz band".
[0201] The above procedure allows to implement the switching of the
operation frequencies at appropriate timing, by linking with the
application requiring high real-timeliness in the wireless
communication.
Other Modification Examples
[0202] It is to be noted that although the present invention is
described based on aforementioned embodiment, the present invention
is obviously not limited to such embodiment. The following cases
are also included in the present invention.
[0203] Each of the aforementioned apparatuses is, specifically, a
computer system including a microprocessor, a ROM, a RAM, a hard
disk unit, a display unit, a keyboard, a mouse, and the so on. A
computer program is stored in the RAM or hard disk unit. The
respective apparatuses achieve their functions through the
microprocessor's operation according to the computer program. Here,
the computer program is configured by combining plural instruction
codes indicating instructions for the computer, in order to achieve
predetermined functions.
[0204] A part or all of the constituent elements constituting the
respective apparatuses may be configured from a single System-LSI
(Large-Scale Integration). The System-LSI is a super-multi-function
LSI manufactured by integrating constituent elements on one chip,
and is specifically a computer system configured by including a
microprocessor, a ROM, a RAM, and so forth. The System-LSI is a
super-multi-function LSI manufactured by integrating constituent
elements on one chip, and is specifically a computer system
configured by including a microprocessor, a ROM, a RAM, and so
forth. A computer program is stored in the RAM. The respective
apparatuses achieve their functions through the microprocessor's
operation according to the computer program.
[0205] A part or all of the constituent elements constituting the
respective apparatuses may be configured as an IC card which can be
attached and detached from the respective apparatuses or as a
stand-alone module. The IC card or the module may also include the
aforementioned super-multi-function LSI. The IC card or the module
achieves its function through the microprocessor's operation
according to the computer program. The IC card or the module may
also be implemented to be tamper-resistant.
[0206] The present invention may be a method of the above. The
present invention may be a computer program for realizing the
previously illustrated method, using a computer, and may also be a
digital signal including the computer program.
[0207] Furthermore, the present invention may also be realized by
storing the computer program or the digital signal in a computer
readable recording medium such as flexible disc, a hard disk, a
CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray Disc),
and a semiconductor memory. Furthermore, the present invention also
includes the digital signal recorded in these recording media.
[0208] Furthermore, the present invention may also be realized by
the transmission of the aforementioned computer program or digital
signal via a telecommunication line, a wireless or wired
communication line, a network represented by the Internet, a data
broadcast and so forth.
[0209] The present invention may also be a computer system
including a microprocessor and a memory, in which the memory stores
the aforementioned computer program and the microprocessor operates
according to the computer program.
[0210] Furthermore, by transferring the program or the digital
signal by recording onto the aforementioned recording media, or by
transferring the program or digital signal via the aforementioned
network and the like, execution using another independent computer
system is also made possible.
[0211] The above embodiment and the modification examples may be
combined respectively.
[0212] The embodiment of the present invention has been described
with reference to the diagrams, however, the present invention is
not limited to the embodiment illustrated. It is possible to add,
to the embodiment illustrated, various corrections or modifications
along with the full scope of equivalents to the present
invention.
INDUSTRIAL APPLICABILITY
[0213] An access point terminal and a wireless communication
terminal according to the present invention are useful in a
wireless LAN network which switches an operation frequency
depending on an application.
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