DESCRIPTION
T i t l e o f I n v e n t i o n
WIRELESS TRANSFER DEVICE AND METI-IOD FOR CONTROL OF
WIRELESS TRANSFER BAND
5
Technical Field
[OOO 11
The invention relates to a wireless transfer device and a method
for control of w i r e l e s s t r a n s f e r band.
10
Background Art
[0002]
A w i r e l e s s t r a n s f e r d e v i c e is known, i n which a packet s i g n a l
received from a wired t r a n s f e r path is transmitted to an opposite
15 s t a t i o n which is opposed v i a a wireless t r a n s f e r path on a one-to-one
basis and t h e opposite station outputs t h e packet s i g n a l t o t h e wired
transfer p a t h a g a i n .
[0003]
In a common technology on wireless t r a n s f e r , i f a multi-value
20 number of a w i r e l e s s modulation scheme is increased in t h e same
w i r e l e s s r e c e p t i o n e l e c t r i c f i e l d l e v e l , wireless t r a n s f e r capacity i s
increased and e r r o r t o l e r a n c e of the wireless t r a n s f e r path is
deteriorated. On t h e c o n t r a r y , if the multi-value number of the
modulation scheme is decreased in the same wireless reception
25 electric field l e v e l , t h e w i r e l e s s transfer capacity i s reduced and high
error t o l e r a l ~ c ec an be secured. Namely, i f t h e multi-value number
of t h e wireless lnodulatioll scherne is decreased in a situation in which
the r e c e p t i o l ~e lectric field level is reduced, though t h e wireless
transfer capacity is reduced, high e r r o r t o l e r a n c e c a n be obtained and
l i n e q u a l i t y can be kept.
[0004]
G e n e r a l l y , t r a n s m i s s i o n capacity o f t h e w i r e l e s s transfer path
5 t e n d s t o be s m a l l compared with t h e wired t r a n s f e r path. However,
since t r a f f i c is rapidly increased with recent rapid expansion of a
mobile phone network and increase o f d a t a communication use, it is
strongly desired to s e c u r e l a r g e t r a n s f e r c a p a c i t y in t h e wireless
transfer path.
10 [0005]
As one of t e c h n i q u e s t o secure l a r g e r t r a n s f e r capacity of the
wireless t r a n s f e r p a t h , an a d a p t i v e modulation function i s known.
When t h e m u l t i - v a l u e number o f the w i r e l e s s modulation scheme is
increased, compared with a normal o p e r a t i o n c o n d i t i o n , i n a s t a t e i n
I5 which t h e wireless reception electric f i e l d l e v e l i s high and the line
q u a l i t y i s h i g h , l a r g e r t r a n s f e r capacity can be acquired by using a
wireless t r a n s f e r d e v i c e with t h e a d a p t i v e modulation function.
[0006]
However, since the wireless transfer capacity which is used
20 with modulation scheme changeover c h a n g e s , t h e wireless t r a n s f e r
device with t h e a d a p t i v e modulation f u n c t i o n needs t o carry out
suppression control o f a n amount o f t r a f f i c t o be s e n t t o t h e wireless
transfer path by f o l l o w i n g t h e change. I f s u p p r e s s i o n control of the
wireless t r a n s f e r c a p a c i t y and t h e amount o f t r a f f i c i s concurrently
25 carried o u t when the control i s c a r r i e d out, traffic loss in transferring
traffic and f l u c t u a t i o n o f transfer d e l a y t i m e due t o influence of
t r a n s i e n t buffering control, and the l i k e , may occur.
[0 0 0 71
Accordingly, in the wireless transfer device which t r a n s f e r s
highly important t r a f f i c i n which it is desirable not to generate t r a f f i c
loss and f l u c t u a t i o n o f t r a n s f e r delay t i m e , t h e problem is required to
be solved.
5 [O008]
Various proposals have been made, on a method f o r securing a
r e c e p t i o n e l e c t r i c f i e l d margin for maintaining a l i n e by using t h e
a d a p t i v e modulation f u n c t i o n c o n t r o l l i n g t h e w i r e l e s s modulation
scheme, and for maintaining a t r a n s f e r f u n c t i o n of important t r a f f i c
10 when t h e l i n e q u a l i t y of t h e w i r e l e s s transfer path.
For example, P a t e n t L i t e r a t u r e 1 discloses a method for
monitoring t h e w i r e l e s s t r a n s f e r capacity and controlling a s i g n a l
band to be t r a n s m i t t e d t o t h e w i r e l e s s transfer p a t h depending on
change o f t h e w i r e l e s s transfer capacity, in the system in which t h e
1s t r a n s f e r capacity of the wireless transfer p a t h on t h e b a s i s of the
a d a p t i v e modulation c o n t r o l . By carrying o u t t h e method,
unnecessary t r a f f i c congestion s i t u a t i o n can be avoided and transfer
rate and transfer q u a l i t y o f a n i m p o r t a n t t r a f f i c can be maintained.
20 Citation List
Patent Literature
[OOO9]
PTL 1 : Japanese P a t e n t A p p l i c a t i o n Laid-Open No. 20 11 -239322
25 Summary o f I n v e n t i o n
Technical Problem
[OO 1 O]
5
However, i n a common method f o r maintaining t r a n s f e r r a t e
and t r a n s f e r q u a l i t y of an important t r a f f i c , a f t e r wireless t r a n s f e r
c a p a c i t y c h a n g e s , a t r a n s f e r band of a packet s i g n a l transmitted t o a
w i r e l e s s t r a n s f e r p a t h is c o n t r o l l e d depending on t h e change.
5 T h e r e f o r e , when a d a p t i v e modulation control i s c a r r i e d o u t so that the
w i r e l e s s t r a n s f e r c a p a c i t y is r e d u c e d , a n operation for reducing t h e
transfer band o f t h e packet s i g n a l t o be transmitted l a t e t o t h e wireless
t r a n s f e r p a t h is carried out with r e s p e c t t o reduction control o f t h e
w i r e l e s s t r a n s f e r c a p a c i t y , a s i t u a t i o n i n which the transfer band of
10 t h e p a c k e t s i g n a l e x c e s s e s t h e w i r e l e s s t r a n s f e r capacity temporarily
occurs. I n such c a s e , problems e x i s t , i n which a high p r i o r i t y packet
i s l o s t and f l u c t u a t i o n of t r a n s f e r d e l a y t i m e occurs.
S o l u t i o n t o Problem
I5 [0011]
A wireless transfer d e v i c e o f t h e i n v e n t i o n is a wireless t r a n s f e r
d e v i c e f o r controlling a w i r e l e s s modulation scheme and a t r a n s f e r
band of a packet signal, which i n c l u d e s a t r a n s f e r band control unit
which decides upon t h e t r a n s f e r band on t h e b a s i s of a r e s u l t of a
20 comparison of communication q u a l i t y i n f o r ~ n a t i o no f wireless
communication, and a predetermined band control threshold v a l u e , a
modulation scheme control u n i t which d e c i d e s on a modulation
scheme on t h e b a s i s o f a result of a comparison o f t h e communication
quality information and a predetermined modulation control threshold
25 v a l u e , a transmission p r o c e s s u n i t which c o n t r o l s a transfer band f o r a
packet s i g n a l on t h e b a s i s of t h e t r a n s f e r band decided upon by the
transfer band control u n i t , and o u t p u t s the packet signal, and a
wireless trallsceiver u n i t which performs a modulation process 011
the packet s i g n a l output by the transmission process unit, 011 the basis
o f t h e modulation scheme decided upon by the modulation scheme
control unit, wherein t h e band control threshold value and the
modulation c o n t r o l threshold v a l u e a r e d i f f e r e n t v a l u e s .
[OO12]
5 A method for control o f w i r e l e s s t r a n s f e r band of the invention
i s a method for a c q u i r i n g communication q u a l i t y information of
w i r e l e s s communication, and deciding upon a t r a n s f e r band and a
modulation scheme, on the basis of the acquired communication
q u a l i t y i n f o r m a t i o n , and i n c l u d e s d e c i d i n g upon t h e transfer band and
10 t h e modulation scheme so that changeover of the transfer band is
carried o u t p r i o r t o changeover of t h e modulation scheme w h i l e
communication q u a l i t y i s deteriorated.
Advantageous E f f e c t s o f I n v e n t i o n
IS [OO13]
Loss of the high p r i o r i t y packet and transient fluctuation of
t r a n s f e r delay time are avoided.
Bri'ef D e s c r i p t i o n o f Drawings
[00 141
[Fig. 11 Fig. 1 i s a block diagram o f a w i r e l e s s ' t r a n s f e r d e v i c e of an
exemplary embodiment 1.
[Fig. 21 Fig. 2 i s a block diagram o f a wireless transfer device of the
25 exemplary embodiment 1 .
[Fig. 3A] Fig. 3A i s a diagram i l l u s t r a t i n g t r a n s i t i o n of a time and a
reception electric f i e l d l e v e l in t h e exemplary embodiment 1 .
[Fig. 3B] Fig. 3B i s a diagram i l l u s t r a t i n g t r a n s i t i o n of a scheme to be
changed depending on the t i m e and t h e reception electric field in the
exemplary embodiment 1.
[Fig. 3C] Fig. 3C is a diagram illustrating t r a n s i t i o n o f wireless
5 transfer c a p a c i t y t o be changed depending on t h e t i m e and the
reception e l e c t r i c f i e l d in t h e exemplary embodiment 1.
[Fig. 3D] Fig. 3D i s a diagram illustrating transition of a t r a n s f e r
band of a p a c k e t s i g n a l t o be changed depending on the time and the
reception e l e c t r i c f i e l d in t h e exemplary embodiment 1.
10 [Fig. 41 F i g . 4 is a diagram illustrating an example o f relationship of
reception electric field information (X), t h e modulation scheme, t h e
wireless t r a n s f e r c a p a c i t y , and the packet t r a n s f e r band in the
exemplary embodiment 1.
15 Description o f Embodiments
[OO 151
Exemplary embodiment 1
By referring to drawings, an exemplary embodiment o f the
invention i s explained. F i g . 1 is a block diagram i l l u s t r a t i n g one
20 exemplary embodiment of t h e i n v e n t i o n .
[0016]
A w i r e l e s s t r a n s f e r d e v i c e 100 includes a transmission process
unit 11, a w i r e l e s s t r a n s c e i v e r u n i t 1 2 , a t r a n s f e r band control unit 13,
and a modulation scheme c o n t r o l u n i t 1 4 . The w i r e l e s s transfer
25 device 100 i s connected t o a wireless t r a n s f e r p a t h 3.
[00 171
The t r a n s f e r p r o c e s s unit 11 reads a packet s i g n a l from a high
p r i o r i t y buffer 22 and a low priority buffer 23, and outputs to the
wireless transceiver unit 1 2 . At this time, tllc transmission process
unit 11 controls a transfer band of t h e packet s i g n a l to be outputted to
t h e w i r e l e s s t r a n s c e i v e r unit 12 on t h e b a s i s of a transfer band control
signal received from the t r a n s f e r band control u n i t 1 3 .
[00 181
5 The wireless transceiver u n i t 12 converts the packet signal
received from t h e t r a n s m i s s i o n p r o c e s s unit 11 into a wireless transfer
signal and outputs to the wireless transfer p a t h 3 . The wireless
t r a n s c e i v e r u n i t 12 a c q u i r e s communication quality information of the
w i r e l e s s t r a n s f e r path 3. I n e x p l a n a t i o n s below, a reception electric
10 field level is used as t h e communication q u a l i t y information. The
w i r e l e s s t r a n s c e i v e r u n i t 12 a c q u i r e s a reception electric f i e l d l e v e l of
a w i r e l e s s s i g n a l used for d e c i s i o n o f l i n e quality, generates reception
electric field i n f o r m a t i o n , and informs the t r a n s f e r band control unit
13 and t h e modulation scheme control u n i t 14. F u r t h e r , t h e wireless
15 transceiver unit 12 c o n t r o l s a modulation scheme and wireless
t r a n s f e r capacity of the wireless transfer path 3 on t h e b a s i s o f
modulation scheme i n f o r m a t i o n r e c e i v e d from the modulation scheme
control unit 14. The w i r e l e s s t r a n s c e i v e r unit 12 extracts a packet
signal from a w i r e l e s s t r a n s f e r s i g n a l received from another wireless
20 t r a n s f e r d e v i c e ( n o t shown) which is in a communication s t a t e with a
wireless transfer device 200 via the wireless t r a n s f e r p a t h 3 .
[0019]
The transfer band control unit 13 controls a transfer band of a
packet s i g n a l which can be secured in t h e wireless transfer path on the
25 b a s i s o f t h e reception electric f i e l d information informed from the
wireless transceiver unit 12. Specifically, the transfer band control
unit 13 compares t h e reception electric field l e v e l i d e n t i f i e d by the
reception electric field information with a predetermined band control
threshold v a l u e , generates the transfer band control s i g n a l on the
9
basis of a r e s u l t o f t h e comparison, and outputs to t h e transmission
process u n i t 1 1 .
[0020]
The modulation scheme c o n t r o l u n i t 14 generates the
5 modulation scheme information by selecting a modulation scheme for
maintaining the line quality of the wireless transfer path a t a
predetermined level, on t h e b a s i s of the reception electric field
information informed from t h e wireless transceiver u n i t 1 2 , and
o u t p u t s t o the wireless t r a n s c e i v e r u n i t 12. Specifically, the
10 modulation scheme control unit 14 compares t h e r e c e p t i o n electric
f i e l d l e v e l i d e n t i f i e d by the r e c e p t i o n e l e c t r i c field with a
predetermined modulation c o n t r o l t h r e s h o l d value, g e n e r a t e s t h e
modulation control s i g n a l by s e l e c t i n g t h e modulation scheme on the
basis of t h e r e s u l t of the comparison, and outputs t o t h e wireless
15 transceiver unit 12.
LO02 11
In the exemplary embodiment of the invention, the band control
threshold value used i n t h e t r a n s f e r band control unit 13 i s d i f f e r e n t
from t h e modulation control t h r e s h o l d v a l u e used i n the modulation
20 scheme control unit 14. S p e c i f i c a l l y , when t h e r e c e p t i o n electric
f i e l d l e v e l is deteriorated, that is, when t h e communication quality is
d e t e r i o r a t e d , t h e band control t h r e s h o l d v a l u e and t h e modulation
control threshold value are set so that transfer band reduction control
is carried o u t p r i o r t o reduction o f t h e wireless t r a n s f e r capacity by
25 modulation c o n t r o l . By carrying out such control, loss of the packet
s i g n a l and t r a n s i e n t f l u c t u a t i o n of transfer delay time are avoided.
[0022]
Exemplary embodimellt 2
F i g . 2 is a block diagram i l l u s t r a t i n g one exemplary
embodiment of the invention. The wireless transfer device 200 with
an a d a p t i v e modulation function is connected t o a wired t r a n s f e r path
2 and t h e w i r e l e s s transfer path 3. The w i r e l e s s t r a n s f e r d e v i c e 200
5 includes a priority decision c i r c u i t 2 1 , t h e high p r i o r i t y buffer 22, the
low p r i o r i t y buffer 23, a transmission circuit 24, a wireless
transceiver circuit 25, a t r a n s f e r band control circuit 26, and a
modulation scheme control c i r c u i t 2 7 .
[0023]
10 The p r i o r i t y d e c i s i o n circuit 21 decides upon transfer priority
of a p a c k e t s i g n a l received from the wired transfer path 2 on t h e basis
of a predetermined priority d e c i s i o n c o n d i t i o n . The p r i o r i t y
decision c i r c u i t 21 o u t p u t s a p a c k e t s i g n a l with high t r a n s f e r p r i o r i t y
to the high priority buffer 2 2 , and o u t p u t s a packet signal with low
I5 transfer priority to t h e low p r i o r i t y buffer 23. As t h e p r i o r i t y
decision condition by t h e p r i o r i t y decision circuit 2 1 , a d d r e s s
information, a priority i d e n t i f i e r , and the l i k e , described in t h e packet
s i g n a l can be employed.
[0024]
'The h i g h p r i o r i t y buffer 22 and the low p r i o r i t y buffer 23
temporarily store the packet s i g n a l r e c e i v e d v i a t h e p r i o r i t y decision
c i r c u i t 2 1 .
[0025]
The transmission circuit 24 c o n t r o l s t h e transfer band of the
25 packet signal to be outputted t o t h e w i r e l e s s transceiver c i r c u i t 25 on
the basis o f t h e t r a n s f e r band control signal received from t h e t r a n s f e r
band control circuit 2 6 . The transmission circuit 24 reads t h e packet
signal from the high p r i o r i t y buffer 22 and t h e low priority bufler 23,
and o u t p u t s t o tllc wireless transceiver c i r c u i t 2 5 .
[0026]
The w i r e l e s s t r a n s c e i v e r c i r c u i t 25 c o n v e r t s t h e packet s i g n a l
received from t h e t r a n s m i s s i o n circuit 24 into a wireless t r a n s f e r
signal and o u t p u t s t o t h e w i r e l e s s t r a n s f e r p a t h 3 . The wireless
5 transceiver c i r c u i t 25 a c q u i r e s communication q u a l i t y information of
the wireless t r a n s f e r p a t h 3. S p e c i f i c a l l y , t h e wireless transceiver
c i r c u i t 25 acquires a r e c e p t i o n e l e c t r i c f i e l d l e v e l of a wireless signal
used f o r decision of line quality t o g e n e r a t e reception electric field
i n f o r m a t i o n and informs t h e t r a n s f e r band control c i r c u i t 26 and t h e
10 modulation scheme c o n t r o l circuit 27. The wireless transceiver
c i r c u i t 25 extracts the packet signal from the wireless transfer signal
received, via t h e w i r e l e s s t r a n s f e r p a t h 3, from a wireless t r a n s f e r
device (not shown) o p p o s i t e t o t h e w i r e l e s s transfer d e v i c e 200 and
outputs t o t h e wired t r a n s f e r path 2. The wireless transceiver c i r c u i t
15 25 controls t h e modulation scheme and the wireless t r a n s f e r capacity
of the w i r e l e s s t r a n s f e r path 3 on the b a s i s o f modulation scheme
information r e c e i v e d from t h e modulation scheme control c i r c u i t 27.
[0027]
The transfer band control c i r c u i t 26 c o n t r o l s a t r a n s f e r band of
20 a packet s i g n a l which c a n be secured in the wireless t r a n s f e r path on
the basis o f t h e r e c e p t i o n e l e c t r i c field information received from t h e
wireless transceiver unit 2 5 . S p e c i f i c a l l y , t h e transfer band control
circuit 26 g e n e r a t e s the transfer band control signal 011 the basis of a
result o f t h e d e c i s i o n on t h e reception electric field information and
25 outputs to t h e t r a n s m i s s i o n circuit 24. In other words, t h e t r a n s f e r
band control c i r c u i t 26 g e n e r a t e s the transfer band control s i g n a l on
the basis o f t h e r e l a t i o n s h i p between the reception electric field level
identified by t h e r e c e p t i o n e l e c t r i c f i e l d information and a
predetermined band control threshold v a l u e , and outputs t h e t r a n s f e r
band control s i g n a l t o t h e t r a n s m i s s i o n circuit 24.
[0028]
The modulation scheme c o n t r o l circuit 27 receives the
5 reception e l e c t r i c f i e l d i n f o r m a t i o n from t h e wireless transceiver
circuit 25 and m o n i t o r s . The modulation scheme control c i r c u i t 27
selects a modulation scheme i n which line q u a l i t y o f t h e wireless
t r a n s f e r p a t h is maintained a t a predetermined constant l e v e l ,
g e n e r a t e s modulation scheme i n f o r m a t i o n , and outputs t o t h e wireless
10 transceiver circuit 2 5 . I n o t h e r words, the modulation scheme
control circuit 27 selects a modulation scheme on t h e b a s i s of the
relationship between t h e r e c e p t i o n e l e c t r i c f i e l d l e v e l i d e n t i f i e d by
the reception electric field i n f o r m a t i o n and a predetermined
modulation control threshold value, generates modulation scheme
15 information, and o u t p u t s t o the wireless transceiver c i r c u i t 25.
[0029]
N e x t , o p e r a t i o n s i n which t h e w i r e l e s s transceiver c i r c u i t 25,
t h e t r a n s f e r band control circuit 26, and t h e modulation scheme
control c i r c u i t 27 control a modulation scheme, wireless t r a n s f e r
20 capacity, and a transfer band of a p a c k e t s i g n a l , depending on a
reception electric f i e l d l e v e l of a wireless signal in t h e wireless
transfer path 3 a r e d e s c r i b e d in d e t a i l using F i g . 3 and Fig. 4.
[0030]
Fig. 3 shows examples o f graphs illustratiilg r e l a t i o n s between
25 t h e reception electric f i e l d l e v e l of wireless signal in wireless
transfer path 3 and t h e modulation scheme, t h e wireless t r a n s f e r
capacity, and the transfer band of t h e packet signal. Times t 11, t 12,
t2 1 , t 2 2 , t 3 1 . t32. t4 1 . t42 i n Fig. 3A t o F i g . 3D a r e times conlnlon to
the same s i g h s one a n o t h e r . Reception electric field levcls tlll I .
th21 a r e the band control threshold v a l u e s . Reception electric field
levels th12, t h 2 2 a r e the modulation control threshold v a l u e s .
1003 11
Fig. 3A is a diagram illustrating t r a n s i t i o n o f a time and the
5 reception e l e c t r i c f i e l d l e v e l , and one example in which t h e reception
electric f i e l d l e v e l changes with elapse of time. It is shown, in the
reception e l e c t r i c f i e l d l e v e l s t h l l and th22, t h l l is a higher
reception e l e c t r i c f i e l d l e v e l and in a s t a t e in which higher line
quality can be maintained.
10 100321
Fig. 3B shows t r a n s i t i o n o f a time and the modulation scheme,
and i t i s s h o w n , i n modulation schemes m3 and m l , m3 selects a
modulation scheme w i t h more multi-values.
[0033]
15 Fig. 3C shows t r a n s i t i o n o f a time and the wireless t r a n s f e r
c a p a c i t y , t h e w i r e l e s s t r a n s f e r capacity conjugates and changes
depcndiilg on change of t h e modulation scheme of Fig. 3R. It is
shown, in t r a n s f e r c a p a c i t y c3 and c l , c3 i s l a r g e r wireless t r a n s f e r
capacity.
20 LO0341
Fig. 3D shows transition of a time and t h e t r a n s f e r band o f t h e
p a c k e t s i g n a l , and it is shown, i n p a c k e t t r a n s f e r bands pc3 and p c l ,
pc3 secures a band which c a n transfers more packet signals.
LO03 51
2 5 Fig. 4 shows o n e example, which i s shown in Fig. 3, on the
r e l a t i o n s h i p between t h e reception electric f i e l d information (X)
outputted by t h e w i r e l e s s t r a n s c e i v e r circuit 25 and the modulation
scheme, the w i r e l e s s t r a n s f e r capacity and the packet transfer band at
the time, as a table. A c o n d i t i o n ( a ) of Fig. 4 shows, f o r exal-nple, if
the reception electric f i e l d information (X) is l a r g e r than t h e
reception e l e c t r i c f i e l d l e v e l t h l l , m3, c3, and pc3 a r e selected a s the
modulation scheme, t h e wireless t r a n s f e r capacity, and t h e packet
t r a n s f e r band, respectively.
5 [0036]
Further a s o n e example of an operation of t h e invention, an
operation which is c a r r i e d out when the reception e l e c t r i c f i e l d l e v e l
of the wireless t r a n s f e r path 3 is decreased from a s t a t e i n which t h e
reception e l e c t r i c f i e l d l e v e l o f t h e wireless t r a n s f e r path 3 i s higher
10 than t h l l of Fig. 3A to a middle-level between th12 and th21 through
th12 is explained in d e t a i l using F i g . 2 to F i g . 4 .
100371
The wireless transceiver c i r c u i t 25 monitors the reception
e l e c t r i c f i e l d l e v e l o f t h e wireless t r a n s f e r path 3 which changes a s
15 time passes and generates t h e r e c e p t i o n e l e c t r i c field information ( X ) ,
and successively informs t h e transfer band control circuit 26, and t h e
modulation scheme control circuit 27.
COO3 81
The t r a n s f e r band control c i r c u i t 26 monitors t h e reception
20 e l e c t r i c f i e l d information (X) received from t h e wireless transceiver
c i r c u i t 2 5 . When d e t e c t i n g t h e e l e c t r i c f i e l d level becomes t h l 1 at
t h e time t l 1 o f F i g . 3 , t h e transfer band control c i r c u i t 26 decides that
a s i t u a t i o n which corresponds t o t h e condition (a) o f F i g . 4 s h i f t s to
t h e condition ( b ) o f F i g . 4 , generates t h e t r a n s f e r band control signal
25 to decrease the packet t r a n s f e r band from pc3 to pc2, and informs t h e
transmission c i r c u i t 24.
100391
The translnission circuit 24 receives the transfer band control
s i g n a l , a d j u s t s an anlount of the packet s i g n a l s to be read from the
15
high p r i o r i t y buffer 22 and t h e low p r i o r i t y buffer 2 3 s o t h a t t h e
transfer band o f t h e p a c k e t s i g n a l outputted t o t h e w i r e l e s s transceiver
c i r c u i t 25 becomes pc2 of Fig. 3D or l e s s , and outputs t h e packet
signal to the w i r e l e s s t r a n s c e i v e r circuit 25. At this t i m e , when i t i s
5 detected t h a t t h e p a c k e t t r a n s f e r band indicated by the transfer band
control s i g n a l changes from pc3 to pc2, t h e p a c k e t s i g n a l which is
currently outputted to t h e w i r e l e s s t r a n s c e i v e r c i r c u i t 25 i s
transmitted w i t h o u t d e l a y , and s u p p r e s s i n g control on the transfer
band i s c a r r i e d out.
10 [0040]
On t h e c o n t r a r y , w h i l e t h e modulation scheme control c i r c u i t
27 monitors t h e r e c e p t i o n e l e c t r i c field information (X) received from
the wireless t r a n s c e i v e r c i r c u i t 2 5 , and decides that the situation
which corresponds t o t h e c o n d i t i o n (a) of F i g . 4 shifts t o t h e condition
15 ( b ) o f F i g . 4, when detecting t h a t t h e reception electric field becomes
t h l 1 at the time t l 1 of F i g . 3 , t h e modulation scheme to be selected i s
not changed in t h e c o n d i t i o n (a) and t h e c o n d i t i o n (b) of Fig. 4, as
shown in the graph of Fig. 3B, the modulation scheme m3 is
maintained.
20 [0041]
Further, when time p a s s e s t o be a t t i m e t 1 2 , t h e t r a n s f e r band
control c i r c u i t 26 and t h e modulation scheme control c i r c u i t 27 detect
that t h e reception electric f i e l d l e v e l becomes t h 1 2 a t t h e time t 1 2 of
Fig. 3, from t h e r e c e p t i o n e l e c t r i c field information (X) received from
25 the wireless t r a n s c e i v e r c i r c u i t 2 5 , and decide t h a t t h e s i t u a t i o n which
corresponds t o the condition (b) of F i g . 4 shifts t o t h e condition (c) of
Fig. 4.
100421
At t h i s t i m e , though t h e t r a n s f e r band control s i g n a l generated
by the transfer band control circuit 26 does not change i n t h e s i t u a t i o n
of t h e p a c k e t t r a n s f e r band pc2, since the modulation scheme t o be
s e l e c t e d on the c o n d i t i o n ( b ) is d i f f e r e n t from t h e modulation scheme
5 to be selected on the c o n d i t i o n ( c ) , t h e modulation scheme control
circuit 27 generates a modulation scheme control s i g n a l t o convert the
modulation scheme from m3 to m2 and informs the wireless
transceiver circuit 25.
[0043]
10 The wireless transceiver circuit 25 changes t h e modulation
scheme o f t h e wireless t r a n s f e r p a t h from m3 to m2 on t h e basis o f t h e
modulation scheme c o n t r o l s i g n a l , and the wireless t r a n s f e r capacity
is reduced from c3 to c2 as shown in Fig. 3C therewith. Since t h e
packet t r a n s f e r band i s already reduced to pc2 at t h e t i m e t12, the
15 packet s i g n a l received from t h e transmission c i r c u i t 24 is not
influenced by r e d u c t i o n o f t h e w i r e l e s s t r a n s f e r capacity from c3 to
c2.
[0044]
As described above, by carrying o u t reduction control of the
20 packet t r a n s f e r band p r i o r t o reduction of t h e wireless t r a n s f e r
capacity by changeover o f t h e modulation scheme in t h e s i t u a t i o n in
which t h e reception electric f i e l d l e v e l of t h e w i r e l e s s t r a n s f e r path 3
is decreased, by making a difference between t h e modulation control
threshold value as the standard forjchangeover of the modulation
25 scheme and the band c o n t r o l t h r e s h o l d value a s t h e standard for
changeover o f the transfer band of t h e packet signal, modulation
scheme changeover by t h e a d a p t i v e modulatioll without a f f e c t i n g a
transferring packet s i g n a l and the reduction control of the wireless
transfer capacity therewith can be c a r r i e d out.
[0045]
Thereby when the reception electric f i e l d l e v e l o f t h e wireless
t r a n s f e r path is lowered and the modulation scheme of the wireless
transfer p a t h , t h e wireless t r a n s f e r capacity and the transfer band of
5 the packet s i g n a l a r e controlled so that the wireless t r a n s f e r capacity
is reduced, the reduction control o f the transfer band of the packet
signal to be transmitted t o t h e wireless t r a n s f e r path can be carried
out prior to the reduction control of t h e wireless t r a n s f e r capacity.
When the reception e l e c t r i c f i e l d l e v e l of t h e wireless t r a n s f e r path i s
10 improved, and t h e modulation scheme of the wireless t r a n s f e r p a t h ,
the wireless t r a n s f e r capacity and the transfer band of the packet
signal are controlled so that the wireless t r a n s f e r capacity i s enlarged,
enlargement control of the wireless t r a n s f e r capacity can be carried
out prior to expansion control of the transfer band o f t h e packet s i g n a l .
15 Therefore, l o s s of the packet s i g n a l with high p r i o r i t y and transient
fluctuation o f the t r a n s f e r delay time can be avoided by change o f the
wireless t r a n s f e r capacity with modulation scheme changeover.
[0046]
The invention is not limited to t h e above described exemplary
20 embodiments, and various changes c a n be made within t h e scope o f
the invention.
For example, t h e wireless t r a n s f e r device related to the
exemplary embodiments of the invention may not necessarily be a
device connected t o o t h e r d e v i c e s using a c a b l e , and sound inputting
25 means and data inputting means may be included in the wireless
transfer device.
In t h e exemplary embodiment o f t h e invention shown in Fig. 2,
,
the packet s i g n a l reccived from t h e wired transmission path is divided
to two p r i o r i t y l e v e l s via tllc p r i o r i t y decision c i r c u i t 21 to be stored
18
in t h e high p r i o r i t y buffer 22 and the low p r i o r i t y buffer 2 3 .
However d i v i s i o n of the priority levels may n o t be two.
In the exemplary embodiment of t h e i n v e n t i o n shown i n Fig. 2 ,
the e l e c t r i c f i e l d level of the wireless s i g n a l i s used f o r decision of
5 t h e l i n e q u a l i t y o f t h e w i r e l e s s t r a n s f e r path. The d e c i s i o n scheme
of t h e l i n e quality i s n o t l i m i t e d t o the method, f o r example, a bit
e r r o r r a t e of a w i r e l e s s l i n e o r a SN ratio ( S i g n a l Noise Ratio) may be
used.
COO471
10 This application is based upon and c l a i m s t h e benefit of priority
from Japanese P a t e n t A p p l i c a t i o n No. 2012-1 56324, filed on July 1 2 ,
2012, the d i s c l o s u r e o f which is incorporated herein in i t s e n t i r e t y by
reference.
I5 Industrial a p p l i c a b i l i t y
[0048]
This i n v e n t i o n c a n be used as a communication device for
infrastructure us.ed by a communication operator, and the l i k e , i n
p a r t i c u l a r a fixed wireless transfer d e v i c e u s i n g a microwave o r
20 millimeter wave.
Reference S i g n s List
[0049]
25 2 wired t r a n s f e r p a t h
3 wireless t r a n s f e r path
11 transmission process unit
12 wireless transceiver unit
13 transfer band control unit
14 modulation scheme control unit
2 1 priority decision c i r c u i t
22 high priority buffer
23 low priority buffer
5 24 transmission c i r c u i t
25 wireless transceiver c i r c u i t
26 transfer band control c i r c u i t
27 modulation scheme control c i r c u i t
100 wireless t r a n s f e r device
10 200 wireless t r a n s f e r device
WE CLAIM:
Claim 1. A wireless transfer devicae, comprising:
transfer band c o n t r o l means f o r deciding upon a transfer band,
5 on t h e basis of a r e s u l t of a comparison o f communication quality
information pertaining t o w i r e l e s s communication, and a
predetermined band control threshold value;
modulation scheme c o n t r o l means f o r deciding on a modulation
scheme, on t h e b a s i s of a result of a comparison o f the communication
10 q u a l i t y i n f o r m a t i o n and a predetermined modulation control threshold
value;
t r a n s m i s s i o n p r o c e s s means f o r c o n t r o l l i n g a t r a n s f e r band f o r a
packet signal on t h e b a s i s o f the transfer band decided upon by the
transfer band control means, and outputting t h e packet signal; and
15 w i r e l e s s t r a n s c e i v e r means f o r performing a modulation process
on the packet signal output by the transmission process means, on the
basis of the modulation scheme decided upon by the modulation
scheme control means,
wherein t h e band control threshold value is different from the
20 modulation control threshold value.
Claim 2. The w i r e l e s s t r a n s f e r d e v i c e o f claim 1 , wherein the band
control threshold value and t h e modulation control threshold value are
set so that changeover o f t h e t r a n s f e r band i s c a r r i e d o u t p r i o r to
25 changeover o f the modulation scheme while communicatioil q u a l i t y i s
deteriorated.
Claim 3. The w i r e l e s s t r a n s f e r d e v i c e o f claim 2, wherein the band
c o ~ l t r o lt l ~ r e s h o l dv alue and the modulation c o ~ l t r o lt hreshold value a r e
set so t h a t t h e changeover o f the modulation scheme is c a r r i e d o u t
p r i o r t o t h e changeover o f t h e t r a n s f e r band while the communication
q u a l i t y i s improved.
5 Claim 4. A wireless transfer device, comprising:
transfer band control means f o r deciding upon a t r a n s f e r band,
on the basis of communication quality i n f o r m a t i o n p e r t a i n i n g to
wireless communication;
modulation scheme c o n t r o l means for deciding on a modulation
l o scheme, on the b a s i s o f the communication quality information;
t r a n s m i s s i o n p r o c e s s means f o r c o n t r o l l i n g a t r a n s f e r band f o r a
p a c k e t s i g n a l on t h e b a s i s of the transfer band decided upon by the
transfer band c o n t r o l means, a n d o u t p u t t i n g the p a c k e t s i g n a l ; and
w i r e l e s s t r a n s c e i v e r means f o r performing a modulation process
15 on t h e packet signal output by t h e t r a n s m i s s i o n process means, on the
b a s i s o f the modulation scheme decided upon by t h e modulation
scheme control means,
wherein t h e t r a n s f e r band control means and t h e modulation
scheme control means d e c i d e upon t h e t r a n s f e r band and the
20 modulation scheme, r e s p e c t i v e l y , so t h a t changeover o f t h e transfer
band i s c a r r i e d o u t p r i o r t o changeover of the modulation scheme
w h i l e communication q u a l i t y i s d e t e r i o r a t e d .
Claim 5 . The w i r e l e s s t r a n s f e r d e v i c e o f any one o f claims 1 to 4,
25 wherein a n e l e c t r i c f i e l d l e v e l of the wireless communication i s used
a s t h e c o ~ n m u n i c a t i o iq~u ality i n f o r m a t i o n o f t h e wireless
c o m n ~ u ~ l i c a t i o n .
22
Claim 6. A method f o r control o f wireless t r a n s f e r band for
acquiring communication q u a l i t y information o f wireless
communication, and deciding upon a t r a n s f e r band and a modulation
scheme, on the b a s i s o f the acquired communication quality
5 information, comprising:
deciding upon t h e t r a n s f e r band and the modulation scheme so
t h a t changeover o f t h e transfer band is c a r r i e d out p r i o r to changeover
o f t h e modulation scheme while communication q u a l i t y i s
deteriorated.