1. A wireless transmission device which tl.ansniits an Ethernet signal received from a wired transmission path to an opposite station one-to-one via a wireless transmission path 5 and again outputs the Ethernet signal in the opposite station to the wired transmission path, comprising: a traffic-statistics circuit which accumulates a traffic volume of a time zone-specific Ethernet signal as statistical data, and an adaptive modulation circuit which suppresses a wireless transmission 10 capacity by decreasing a multi-level number of a modulation scheme in a time zone in which the traffic volume is small based on the statistical data accumulated in the trafiic-statistics circuit.

2. A wireless transmission device which transmits an Ethernet signal received from a 15 wired transmission path to an opposite station one-to-one via a wireless transmission path and again outputs the Ethernet signal in the opposite station to the wired transmission path, comprising: a traffic-statistics circuit which accumulates a traffic volume of a time zone-specific Ethernet signal as statistical data and generates statistical traffic volume 20 information by calculating a mode value of trafiic volume information of the same time zone based on the traffic volume information accumulated in a predetermined fixed period; and an adaptive modulation circuit which suppresses wireless transmission power corresponding to a received electric field margin of the wireless transmission path 25 generated by decreasing a multi-level number of a modulation scheme in a range in 20 which fixed line quality is securable.

3. A wireless transmission device which transmits an Ethernet signal received from a wired transmission path to an opposite station one-to-one via a wireless transmission path 5 and again outputs the Ethernet signal in the opposite station to the wired transmission path, comprising: a traffic-statistics circuit which accumulates a traffic volun~eo f a time zone-specific Ethernet signal as statistical data and generates statistical traffic volu~ne information by calculating a mode value of traffic volume infor~nationo f the same time 10 zone based on the traffic volume information accumulated in a predetermined fixed period; and an adaptive modulation circuit which reduces a wireless transmission capacity by decreasing a multi-level number of a modulation scheme in a time zone in which the traffic volu~neis small based on the statistical data accumulated in the traffic-statistics 15 circuit and suppresses wireless transmission powcr corresponding to a received clectric field margin of the wireless transmission path generated by decreasing the multi-level number of the modulation scheme in a range in which fixed line quality is securable.

4. A wireless transmission device provided with the adaptive modulation circuit 20 according to any one of Claitns 1 to 3, comprising: the adaptive modulation circuit including a ~nodulations cheme-setting circuit which selects a predetermined modulation scheme and wireless transmission power according to statistical traffic volume information obtained from the traffic-statistics circuit to generate wireless transmission capacity information, modulation scheme 25 information, and wireless transnlission power control information.

5. A control method for an adaptive modulation circuit which transmits an Ethernet signal received from a wired transmission path to an opposite station one-to-one via a wireless transmission path and again outputs the Ethernet signal in the opposite station to 5 tbe wired transmission path, comprising: accumulating a traffic volumc of a time zone-specific Ethernet signal as statistical data; reducing a wireless transmission capacity by decreasing a multi-level nunlber of a modulation scheme in a time zone in which the traffic volume is small based on the 10 statistical data: and suppressing wireless transmission power corresponding to a received electric field margin of a wireless transmission path generated by decreasing the multi-level number of the modulation scheme in a range in which fixed line quality is securable.

DESCRIPTION
CONTROL METI-IOD FOR ADAPTIVE MODULA'rlON CIRCUIT AND
WIRELESS TRANSMISSION DEVICE PROVIDED WITI-I ADAPTIVE
MODULATION CIRCUIT
TECHNICAL FIELD
[OOOl]
The prcsent invention relates to a wireless transmission device provided with an
adaptive modulatioll circuit, which transmits an Ethernet (registered trademark) signal
10 received from a wired transmission path to an opposite station one-to-one via a wireless
transmission path and again outputs the Ethernet signal in the opposite station to the
wired transn~issionp ath, and a control method for the adaptive modulation circuit.
BACKGROUND ART
15 [0002]
As a wireless transmission device of the related art, a wireless transmission
device in which a transmission and rcccption dcvicc cstimatcs a transmission path
situation based on a received signal, satisfies comn~unicationq uality of a fixed level in a
propagation path situation, and determines a modulation scheme representing a highest
20 transmission speed as a first modulation scheme is known (for example, see Patent
Document 1).
The wireless transmission device disclosed in Patent Document 1 detects a
traffic volume of transmission data and determines a modulation scheme representing a
lowcst transmission speed at which the traffic volume can be transmitted as a second
25 modulatioil scheme.
This wireless trans~~~issdioevni ce selects a modulation scheme of a lower
transmission speed within the first modulation schenle and the second ~nodulation
sche~nea s a transmission modulation scheme.
Further, this wireless transnlission device reduces power consumption by
5 sequentially selecting modulation schemes so that a wireless transmission capacity
according to a traffic volume is provided.
[0003]
As a wireless transmission device of the related art, a wireless transmission
device using a comnlunication trafic volume in information for determining
10 cotnmunication capability according to a communication control function is known (for
cxample, see Patent Document 2).
The wireless transmission device disclosed in Patent Document 2 uses a
communication time zone in the information for determining the communication
capability according to the communicatioti control function.
15 This wireless transmission device can implement optimum co~nmunication
capability and optimum power consumption according to the communication traffic
condition and i~nplemenot ptinlu~nc ommunication capability and opti~nu~ponw er
consumption according to the communication time zone.
[0004]
20 In this manner, various proposals for a method of reducing power consumption
of a wireless transmission device by controlling an adaptive modulation circuit and
wireless transmission power based on a traffic volume of a transmission signal have been
made so far.
As general technology, when a multi-level numhcr of the wireless modulation
25 scheme increases, a wireless transmission capacity increases but error tolerance of the
3
wireless transnlission path is degraded. When the multi-level number of the wireless
modulation scheme decreases, the wireless transmission capacity decreases but high error
tolerance is securable.
That is. when a modulation scheme of a small multi-level number is used on the
5 same wireless propagation condition, a good propagation characteristic can be obtained
at lower transmission power.
Normally, it is known that, although the trafic volume is varied in real time,
there is a correlation between an operation time zone and a traffic volume.
In particular, when a discontinuous signal stream is transmitted using a wireless
10 transmission device which continuously performs wireless transmission and reception,
wireless transmission and reception are constantly maintained even in a state in which
there is no traffic to be transmitted.
Because fixed power is constantly consumed even in a situation in which the
traffic volumc has been reduced, power control according to a line statc or traffic volume
15 is required.
[Documents ofthe prior art]
[Patent Documcnts]
[OOOS]
[Patent Document 11
20 Japanese Unexamined Patent Application, First l'ublication No. 2006-165939
[Patent Document 21
Japanese Unexarnined Patent Application, First Publication No. 2005-260414
DISCLOSURE OF 1NVENTION
25 [Problems to be solved by the invention]
4
[0006]
The wireless transmission device of Patent Document 1 can reduce power
consumption by sequentially selecting modulation schemes so that a wireless
transniission capacity according to traffic volume is provided.
5 However, for an adaptive modulation control scheme in cooperation with a
sequentially varying traffic volume in this wireless transn~issiond evice, adaptive
nlodulation control follows instantaneous fluctuation in a transmission signal.
Accordingly, a sufficient power consumption suppression effect is not obtained
in the technology disclosed in Patent Document 1.
10 [0007]
On the other hand, according to the technology disclosed in Patent Document 2,
it is possible to iniplement optimum communication capability and optimum power
consumption according to the co~nmunicationtr affic condition and implement optimum
communication capability and optimum power consumption according to the
15 communication time zone.
However, in the wireless transmission device of Patent Document 2, a process is
performed based on a predetermined infornlation amount.
Accordingly, it is difficult for this device to self-apply with a characteristic of an
actual operation line in order to perform an operation for a fixed predetermined time.
20 [0008]
The present invention has been made to solve the above-described problem, and
an object of the present invention provides a wireless transmission device provided with
an adaptive modulation circuit and a control method for the adaptive modulation circuit
which enable wireless transmission power of a time zone in which a traffic volume is
25 statistically small to be suppressed according to an installation environment and enable
5
an effect of reducing power consunlption to be achieved.
[Means for solving the problem]
[0009]
A wireless transmission devicc provided with an adaptive n~odulation circuit in
5 an aspect of the present invention is a wireless transn~issiond evice which transmits an
Ethernet signal received from a wired transmission path to an opposite station one-to-one
via a wireless transn~ission path and again outputs the Ethernet signal in the opposite
station to the wired transmission path, including: a traffic-statistics circuit which
accumulates a traffic volume of a time zone-specific Ethernet signal as statistical data,
10 wherein a wireless transnlission capacity is reduced by decreasing a multi-level number
of a modulation scheme in a time zone in which the traffic volu~neis small based on the
statistical data accumulated in the traffic-statistics circuit.
[OO lo]
A wireless transmission device providcd with an adaptive modulation circuit in
15 an aspect of the prcsent invention is a wireless transmission device which transmits an
Ethernet signal received from a wired transmission path to an opposite station one-to-one
via a wirclcss transmission path and again outputs the Ethernet signal in the opposite
station to the wired transmission path, including: a traffic-statistics circuit which
accumulates a traffic volume of a time zone-specifi c Ethernet signal as statistical data
20 and generates statistical traffic volunle information by calculating a mode value of traffic
volume information of the same time zone based on the traffic volume information
accumulated in a predetermined fixed period, wherein wireless transmission power
corresponding to a received electric field margin of the wireless transmission path
generated by decreasing a multi-level number of a modulation scheme in a range in
25 which fixed line quality is securable is reduced.
6
[00111
A wireless transmission device provided with an adaptive modulation circuit in
an aspect of the present invention is a wireless transmission device which transmits an
Ethernet signal received from a wired transmission path to an opposite station one-to-one
5 via a wireless transmission path and again outputs the Ethernet signal in the opposite
station to the wired translnission path, including: a traffic-statistics circuit which
accun~ulatesa traffic volume of a time zone-specific Ethernet signal as statistical data
and generates statistical traffic volun~ein formation by calculating a mode value of traffic
volume information of the same time zone based on the traffic volume information
10 accu~nulated in a predetermined fixed period, wherein a wireless transmission capacity is
reduced by decreasing a multi-level number of a nlodulation scheme in a time zone in
which the traffic volulne is small based on the statistical data accumulated in the
traffic-statistics circuit and wireless transmission power corresponding to a received
electric field margin of thc wirclcss transmission path generated by decreasing the
15 multi-level number of the modulation scheme in a range in which fixed line quality is
securable is reduced.
[0012]
The wireless transmission device provided with the adaptive modulation circuit
in the aspect of the present invention includes the adaptive modulation circuit including a
20 modulation scheme-setting circuit which selects a predeternlined modulation scheme and
wireless transmission power according to statistical traffic volume information obtained
from the trafic-statistics circuit to generate wireless transmission capacity information,
modulation scheme information, and wireless transmission power control information.
[OOI 31
25 A control method for an adaptive modulation circuit in an aspect of the prcsent
7
invention is a control method for an adaptive modulation circuit which transmits an
Ethernet signal received fro111 a wired transmission path to an opposite station one-to-one
via a wireless transn~issionp ath and again outputs the Ethernet signal in the opposite
station to the wired transn~issionp ath, including: accumulating a traffic volume of a time
5 zone-specific Ethernet signal as statistical data; reducing a wireless transmission capacity
by decreasing a multi-level number of a modulation scheme in a time zone in which the
traMic volun~eis small based on the statistical data; and reducing wireless transmission
power corresponding to a received electric field margin of a wireless transinission path
generated by decreasing the multi-level number of the modulation scheme in a range in
10 which fixed line quality is securable.
[Effects of the Invention]
[00 141
According to a wireless transmission device provided with an adaptive
modulation circuit and a control mcthod for the adaptive modulation circuit according to
15 the present invention, it is possible to reduce wireless transmission power of a time zone
in which a traffic volun~eis statistically small according to an installation environment
and to reduce power consumption.
BRIEF DESCRIPTION OF THE DRAWINGS
LOO 151
20 FIG. 1 is a block configuration diagram of a wireless transmission device
provided with an adaptive modulation circuit according to an embodiment of the present
invention. (a) of FIG 2 is a time transition diagram of statistical traffic volume
information generated by a traffic-statistics circuit in a control method for the adaptive
modulation circuit according to the embodiment of the present invention. (b) of FIG. 2
25 is a time transition diagram ofa wireless transition capacity selected based on the
8
statistical traffic volunle information received by a nlodnlation scheme-setting circuit
fro111 the traffic-statistics circuit in the control method for the adaptive modulation circuit
according to the embodiment of the present invention. (c) of FIG. 2 is a time transition
diagram of a modulation scheme selected based 011 the statistical traffic volun~e
5 information received by the modulation scheme-setting circuit from the traffic-statistics
circuit in the control inethod for the adaptive modulation circuit according to the
embodiment of the present invention. (d) of FIG. 2 is a time transition diagram of
wireless transmission power selected based on the statistical traffic volun~ein formation
received by the lnodulation scheme-setting circuit from the traffic-statistics circuit in the
10 control method for the adaptive modulation circuit according to the embodiment of the
present invention.
FIG. 3 is a table determined by a relationship between a value of the statistical
traffic volun~ea nd a threshold value in the control method for the adaptive modulation
circuit according to thc embodimcnt of the present invention.
15
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[00 161
Hereinafter, a wireless transnlission device having an adaptive modulation
circuit and a control method for the adaptive modulation circuit according to an
20 embodimcnt of the present invention will be described with reference to the drawings.
As illustrated in FIG. 1, a wireless transn~issiond evice 10 includes an adaptive
n~odulationf unctioil connected to a wired transmission path 11.
The wireless transnlission device 10 is connected to a wireless transmission path
13 via a circulator 12 which separates a wireless transmission signal into a transmission
25 signal and a reception signal.
9
The wireless transnlission device 10 includes a transmission buffer 14. a
transmission circuit 15, a transnlission power control circuit 16, a traffic-statistics circuit
17, a modulation scheme-setting circuit 18, and a reception circuit 19.
[00 171
5 The wireless transmission device 10 outputs an Ethernet signal received from
the wired transmission path 11 to the wireless transmission path 13 via the translnission
buffer 14, the transmission circuit 15, the transn~issionp ower control circuit 16, and thc
circulator 12.
In addition, the wireless transmission device 10 outputs an Ethernet signal
10 received from an opposite station (not illustrated) via the wireless transmission path 13 to
the wired transmission path 11 via the circulator 12 and the reception circuit 19.
[OO 1 81
'The traffic-statistics circuit 17 constantly monitors the Ethernet signal received
from the wired translnission path 11, and accumulates time zone-specific traffic volume
15 information by detecting a traffic volume in predetermined fixed time units.
In addition, the traffic-statistics circuit 17 generates statistical traffic volume
information by calculating a mode value of traffic volume information of the same time
zone based on the traffic volume information accumulated in a predeter~ninedf ixed
period, and notifies the modulation scheme-setting circuit 18 to he described later of the
20 generated statistical traffic volume information.
[0019]
According to the statistical traffic volume information received from the
traffic-statistics circuit 17, the modulation scheme-setting circuit 18 selects a
predetermined modulation scheme and wireless transmission power to generate wireless
25 transmission capacity information, modulation scheme information, and wireless
10
trans~~lissiopno wer control information.
Then, the inodulation scheme-setting circuit 18 outputs the generated wireless
transnlission capacity information, modulation schetne information, and wireless
transmission power control information to each of the transmission buffer 14, the
5 transmission circuit 15, and the transmission power control circuit 16.
[0020]
Next, a process in which the modulation scheme-setting circuit 18 determines a
wirelcss transmission capacity, a modulation scheme, and wireless transmission power in
the control information for the adaptive modulation circuit will be described in detail
10 with reference to (a), (b), (c), and (d) in FIG. 2 and FIG. 3.
(a) of FIG. 2 illustrates the time transition of the statistical traffic volume
information generated by the traffic-statistics circuit 17, and thl and th2 represent
threshold values of a statistical traffic volume 3 1 serving as a criterion for changing a
wirelcss transmission capacity 32, a modulation scheme 33, and wireless transmission
15 power 34.
In addition, in (a) of FIG. 2, times tl, t2, and t3 represent times at which the
statistical traffic volume 3 1 crosses the threshold values thl and th2.
(b), (c), and (d) of FIG. 2 illustrate time transitions of the wireless transmission
capacity 32, the nlodulation scherne 33, and the wireless transmission power 34 selected
20 by the modulation scheme-setting circuit 18 based on the statistical traffic volume
information received from the traffic-statistics circuit 17, respectively.
Then, by referring to a table of relationships between a value of a statistical
traffic volume X and the threshold values thl and th2 illustrated in FIG. 3. the wireless
transmission capacity 32 is determined to be a value of cl to c3, the modulation scheme
25 33 is determined to be a value of ml to m3, and the wireless transmission power 34 is
11
determined to be a value of pl to p3.
[0021]
For example, in (a) of FIG. 2, as in a time zone between the time tl to the time t2,
a condition of thl I X < th2 illustrated in FIG. 3 is established when thc statistical traffic
5 volun~e3 1 is between the threshold value thl and the threshold value th2.
Thus, each of the value of c2 for the wireless transmission capacity, the value of
1112 for the modulation scheme, and the value ofp2 for the wireless transmission power is
selected.
[00221
10 Returning to FIG. 1, the transn~issionb uffer 14 temporarily accumulates an
Ethernet signal when traffic of the Ethernet signal received from the wired transmission
path 11 has been congested.
Simultaneously, the transmission buffer 14 outputs the Ethernet signal according
to the wireless transmission capacity to the transtnission circuit 15 based on the wireless
15 transmission capacity information received from the nlodulation scheme-setting circuit
18.
The transmission circuit 15 selects the wireless nlodulation scheme based on the
modulation scheme information received from the modulation scheme-setting circuit 18,
generates a wireless transmission signal by multiplexing the Ethernet signal received
20 from the transmission buffer 14 into a wireless signal, and outputs the generated wireless
transn~issions ignal to the transmission power control circuit 16.
The transmission power control circuit 16 selects the wireless transn~ission
power based on the wireless transmission power information received from the
modulation scheme-setting circuit 18 and outputs thc wireless transmission signal
25 received from the transmission circuit 15 to the wireless transmission path 13 via the
12
circulator 12.
'fie reception circuit 19 extracts the Ethernet signal multiplexed by the opposite
station (not illustrated) from the wireless reception signal received from the wireless
transmission path 13 via the circulator 12 and outputs the extracted Ethernet signal to the
5 wired transmission path 11.
[0023]
Next, the control method for the adaptive modulation circuit to be executed by
the wireless transmission device 10 will be described in detail with reference to FIGS. 1
to 3 in accordance with the time transition diagrams illustrated in (a), (b), (c), and (d) in
10 FIG.2.
In (a), (b), (c), and (d) of FIG. 2, a time zone up to time tl represents a time zone
in which a traffic volume is statistically small.
Thus, a section in which a control process of decreasing the multi-level number
of the modulation scheme and suppressing transmission powcr for a margin of a received
15 electric field in a range in which line quality is securable is executed is shown.
At this time, the condition corresponds to Condition 1 illustrated in FIG. 3
because the statistical traffic volume 3 1 is less than the threshold value thl.
Thereby, the modulation scheme-setting circuit 18 notifies the transmission
buffer 14 that the wireless transn~issionc apacity 32 is cl, notifies the transmission circuit
20 15 that the modulation scheme 33 is ml, and notifies the transn~issionp ower control
circuit 16 that the wireless transmission power 34 is pl.
100241
In (a), (b), (c), and (d) of FIG 2, the time zone fro111 the time t2 to the time t3
represents a time zone in which the traffic volume is statistically large.
25 Thus, a section in which a control process of securing the transmission capacity
13
by increasing the multi-level number of the modulation scheme and increasing
transmission power in order to secure necessary line quality is executed is shown.
At this time, the condition corresponds to Condition 3 illustrated in FIG. 3
because the statistical traffic volume 3 1 is greater than the threshold value th2.
5 Thereby, the modulation scherne-setting circuit 18 notifies the transmission
buffer 14 that the wireless transmission capacity 32 is c3, notifies the transmission circuit
15 that the modulation schcme 33 is n13, and notifies the transmission power control
circuit 16 that the wireless transmission power 34 is p3.
[0025]
10 In (a), (b), (c), and (d) of FIG. 2, the time zone from the time tl to thc time t2
and a time zone after the time t3 also correspond to Condition 2 illustrated in FIG. 3.
Thus, the modulation scheme-setting circuit 18 notifies the transmission buffer
14 that the wireless transmission capacity 32 is c2, notifies the transmission circuit 15
that the modulation scheme 33 is m2, and notifies the transn~issionp owcr control circnit
15 16 that the wireless transn~issionp ower 34 is p2.
[0026]
In this manner, the wireless transmission dcvicc 10 can absorb an incrcasc in an
instantaneous traffic volume in the transmission buffer 14, and suppress transmission
power in a time zone in which a traffic volume is small based on statistical data.
20 [0027]
In the embodiment of the present invention, statistical traffic volume
information is generated by calculating a mode value of traffic volume information of the
same time zone based on the traffic volume information accumulated in the
traffic-statistics circuit 17.
25 As another embodiment different from the above embodiment, a method of
14
calculating the statistical traffic volu~neis not limited to the mode value, and can also be
executed in a method of obtaining a peak value or an average value.
In addition, as a furthcr different embodiment, it is not necessary for all traffic to
serve as a statistical target and only traffic coincident with a specific condition such as a
5 data size or a trafic type may serve as the statistical target.
[0028]
According to the wireless transmission device 10 provided with the adaptive
modulation circuit of the embodiment as described above, an instantaneous increase in
traffic is absorbed by the transmission buffer 14.
10 Then, according to the wireless transmission device 10 provided with the
adaptive modulation circuit, the traffic-statistics circuit 17 counts a traffic volume of the
Ethernet signal according to each time zonc and accumulates the counted traflic volume
as a statistical traffic volume.
Further, according to the wireless transmission device 10 provided with the
15 adaptive modulation circuit, the wireless transmission capacity is suppressed by
decreasing the multi-level number of the wireless modulation scheme in a time zone in
which the traffic volu~neis small based on the statistical traffic volume accumulated in
the traffic-statistics circuit 17.
Accordingly, in the wireless transmission device 10 provided with the adaptive
20 nlodulation circuit, power consunlption can be reduced by suppressing the wireless
transmission capacity.
[0029]
In addition, according to the wireless transmission device 10 provided with the
adaptive modulation circuit of the embodiment, an instantaneous increase in traffic is
25 absorbed by the transmission buffer 14.
15
Then, according to the wireless transmission device 10 provided with thc
adaptive modulation circuit, the traffic-statistics circuit 17 counts a traffic volun~eo f the
Ethernet signal according to each time zone and accumulates the counted traffic volun~e
as a statistical traffic volume.
5 Further, according to the wireless transmission device 10 provided with the
adaptive modulation circuit, the wireless transmission power is suppressed in a range in
which line quality is securable in a time zone in which the traffic volume is small based
on the statistical traffic volu~nea ccu~nulatedin the traffic-statistics circuit 17.
Accordingly, in the wireless transmission device 10 provided with the adaptive
10 modulation circuit, power consumption can be reduced by suppressing the wireless
transmission capacity.
[0030]
Then, according to the wireless transmission device 10 provided with the
adaptive modulation circuit of the embodiment, an instantaneous increase in traffic is
15 absorbed by the transmission buffer 14.
Then, according to the wireless transmission device 10 provided with the
adaptive modulation circuit, the traffic-statistics circuit 17 counts a traffic volume of the
Ethernet signal according to each time zone and accumulates the counted traffic volume
as a statistical traffic volume.
20 Further, according to the wireless transmission device 10 provided with the
adaptive modulation circuit, the multi-level number of the wireless modulation scheme is
decreased in a time zone in which the traffic volunle is small based on the statistical
traffic volume accumulated in the traffic-statistics circuit 17.
In addition, according to the wireless transmission device 10 provided with thc
25 adaptive modulation circuit, the wireless transmission power is suppressed in a range in
16
which line quality is securable in a time zone in which the traffic volume is small based
on the statistical traflic volunie accuniulated in the traffic-statistics circuit 17.
Accordingly, in the wireless transmission device 10 provided with the adaptive
n~odulationc ircuit, power consumption can be reduced by suppressing the wireless
5 transmission capacity.
[003 11
In addition, the wireless transmission device 10 provided with the adaptive
n~odulationc ircuit according to the embodiment of the present invention includes the
modulation scheme-setting circuit 18 which sclects a prcdctermined modulation scheme
10 and wireless transmission power according to statistical traffic volunie information
obtained from the traffic-statistics circuit 17 to generate wireless transmission capacity
information, modulation scheme information, and wireless transmission power control
infortriation.
Accordingly, in the wireless transmission device 10 provided with the adaptivc
15 modulation circuit, it is possible to intensively control a wireless transmission capacity
and wireless transmission power in a time zone in which the traffic volume is small
according to the modulation scheme-setting circuit 18.
100321
Further, according to the control method for the adaptive modulation circuit of
20 the embodiment, an instantaneous increase in traffic is absorbed, a traffic volume of the
Ethernet signal is counted according to each time zone, and the counted traffic volume is
accumulated as a statistical traffic volume.
Then, according to the control method for the adaptive modulation circuit
according to the embodiment of the present invention, the multi-level number ofthe
25 wireless modulation schcmc is decreased in a time zone in which the traffic volume is
17
small based on the accumulated statistical traffic volume.
Further according to the control method for the adaptive modulation circuit
accordiiig to the embodiment of the present invention, the wireless transmission power is
suppressed in a range in which line quality is securable in a time zone in which the traffic
5 volume is small based on the accumulated statistical traffic volume.
Accordingly, in the control method for the adaptive modulation circuit according
to the elnbodilneilt of the present invetitiot~p, ower consuniption can be reduced by
suppressing the wireless transmission capacity.
[0033]
10 The wireless transmission device provided with the adaptive inodulation circuit
and the control method for the adaptive modulation circuit according to the embodiment
of the present illvention are not limited to the above-described embodiment, and
appropriate modifications and improvements, are possible.
INDUS'I'KIAL API'LICABlLl'l'Y
15 [0034]
As described above, according to a wireless transmission device provided with
an adaptive modulation circuit and a control method for the adaptive modulation circuit,
it is possible to suppress wireless transmission power of a time zone in which a traffic
volume is statistically small according to an installation environment and to reduce
20 power consumption.
As a result of the above, it is possible to apply the present invention to a
communication device for an infi-astructure used by a communication provider or the like,
particularly, a fixed wireless transmission device using microwaves and millimeter waves,
and improve the industrial applicability of the present invention.
25 It is possible to provide a wireless transmission device provided with an
18
adaptivc ltlodulatiolt circuit and a control method for the adaptivc modulation circuit
which enable wireless transmission power ofa time zone in which a traffic volutne is
statistically small to be suppressed according to an installation ellvironment and to reduce
power consumption.
5 [0035]
Priority is claimed on Japanese I'atent Application No. 201 1-13 1019, filed June
13, 201 1, the coiltent of which is i~tcorporatedh erein by reference.
[Description of Reference Symbols]
[0036]
10 10 Wireless transmission device
11 Wired transmission path
13 Wireless transmission path
17 Traffic-statistics circuit
18 Modulation scheme setting circuit

WE CLAIM:
1. A wireless transmission device which tl.ansniits an Ethernet signal received from a
wired transmission path to an opposite station one-to-one via a wireless transmission path
5 and again outputs the Ethernet signal in the opposite station to the wired transmission
path, comprising:
a traffic-statistics circuit which accumulates a traffic volume of a time
zone-specific Ethernet signal as statistical data, and
an adaptive modulation circuit which suppresses a wireless transmission
10 capacity by decreasing a multi-level number of a modulation scheme in a time zone in
which the traffic volume is small based on the statistical data accumulated in the
trafiic-statistics circuit.
2. A wireless transmission device which transmits an Ethernet signal received from a
15 wired transmission path to an opposite station one-to-one via a wireless transmission path
and again outputs the Ethernet signal in the opposite station to the wired transmission
path, comprising:
a traffic-statistics circuit which accumulates a traffic volume of a time
zone-specific Ethernet signal as statistical data and generates statistical traffic volume
20 information by calculating a mode value of trafiic volume information of the same time
zone based on the traffic volume information accumulated in a predetermined fixed
period; and
an adaptive modulation circuit which suppresses wireless transmission power
corresponding to a received electric field margin of the wireless transmission path
25 generated by decreasing a multi-level number of a modulation scheme in a range in
20
which fixed line quality is securable.
3. A wireless transmission device which transmits an Ethernet signal received from a
wired transmission path to an opposite station one-to-one via a wireless transmission path
5 and again outputs the Ethernet signal in the opposite station to the wired transmission
path, comprising:
a traffic-statistics circuit which accumulates a traffic volun~eo f a time
zone-specific Ethernet signal as statistical data and generates statistical traffic volu~ne
information by calculating a mode value of traffic volume infor~nationo f the same time
10 zone based on the traffic volume information accumulated in a predetermined fixed
period; and
an adaptive modulation circuit which reduces a wireless transmission capacity
by decreasing a multi-level number of a modulation scheme in a time zone in which the
traffic volu~neis small based on the statistical data accumulated in the traffic-statistics
15 circuit and suppresses wireless transmission powcr corresponding to a received clectric
field margin of the wireless transmission path generated by decreasing the multi-level
number of the modulation scheme in a range in which fixed line quality is securable.
4. A wireless transmission device provided with the adaptive modulation circuit
20 according to any one of Claitns 1 to 3, comprising:
the adaptive modulation circuit including a ~nodulations cheme-setting circuit
which selects a predetermined modulation scheme and wireless transmission power
according to statistical traffic volume information obtained from the traffic-statistics
circuit to generate wireless transmission capacity information, modulation scheme
25 information, and wireless transnlission power control information.
5. A control method for an adaptive modulation circuit which transmits an Ethernet
signal received from a wired transmission path to an opposite station one-to-one via a
wireless transmission path and again outputs the Ethernet signal in the opposite station to
5 tbe wired transmission path, comprising:
accumulating a traffic volumc of a time zone-specific Ethernet signal as
statistical data;
reducing a wireless transmission capacity by decreasing a multi-level nunlber of
a modulation scheme in a time zone in which the traffic volume is small based on the
10 statistical data: and
suppressing wireless transmission power corresponding to a received electric
field margin of a wireless transmission path generated by decreasing the multi-level
number of the modulation scheme in a range in which fixed line quality is securable.