1. A wireless transmission device comprising: communication means employing an adaptive modulation scheme for 5 sending a first frame to an opposing device through a first wireless transmission path, and receiving a second frame from the opposing device through a second wireless transmission path, the second wireless transmission path having a frequency different from the first wireless transmission path; and multiplex means for multiplexing a plurality of first data signals and a 10 second data signal to generate the first frame, the first data signals being input in parallel at a fixed rate, and the second data signal being input at a variable rate, wherein the multiplex means includes, in the first frame, information relating to a number of multiplexed first data signals. 15 2. The wireless transmission device according to Claim 1, further comprising: separation means for separating, from the second frame, a plurality of third data signals, a fourth data signal, and information relating to a number of multiplexed third data signals, the third data signals being input in parallel to the 20 opposing device at a fixed rate, and the fourth data signal being input to the opposing device at a variable rate, wherein the multiplex means determines the number of multiplexed first data signals according to the number of multiplexed third data signals. 25 3. The wireless transmission device according to Claim 2, wherein the multiplex means equalizes the number of multiplexed first data signals to the number of multiplexed third data signals.

4. The wireless transmission device according to Claim 2 or 3, wherein 30 when the multiplex means determines to reduce the number of multiplexed first data signals, the multiplex means allocates a vacant region in the first frame generated by reduction to multiplexing of the second data signal. #\5'

5. The wireless transmission device according to any one of Claims 1 to 4, wherein the multiplex means selects a data signal to be multiplexed in the first frame from the first data signals according to priorities of the first data signals. 5 6. A wireless transmission device comprising: communication means employing an adaptive modulation scheme for receiving a first frame from an opposing device through a first wireless transmission path, and sending a second frame to the opposing device through a second wireless transmission path, the second wireless transmission path having 10 a frequency different from the first wireless transmission path; separation means for separating, from the first frame, a plurality of first data signals, a second data signal, and information relating to a number of multiplexed first data signals, the first data signals being input in parallel to the opposing device at a fixed rate, and the second data signal being input to the 15 opposing device at a variable rate; and multiplex means for multiplexing a plurality of third data signals and a fourth data signal to generate the second frame, the third data signals being input in parallel to the wireless transmission device at a fixed rate, and the fourth data signal being input to the wireless transmission device at a variable rate, 20 wherein the multiplex means determines a number of multiplexed third data signals according to the number of multiplexed first data signals.

7. The wireless transmission device according to Claim 6, wherein the multiplex means equalizes the number of multiplexed third data signals to the 25 number of multiplexed first data signals.

8. A wireless transmission system comprising: a first wireless transmission device employing an adaptive modulation scheme that sends a first frame through a first wireless transmission path and 30 receives a second frame through a second wireless transmission path, the second wireless transmission path having a frequency different from the first wireless transmission path; and a second wireless transmission device employing the adaptive modulation scheme that receives the first frame from the first wireless transmission device \5: through the first wireless transmission path and transmits the second frame to the first wireless transmission device through the second wireless transmission path, wherein the first wireless transmission device is configured to: multiplex a plurality of first data signals and a second data signal to 5 generate the first frame, the first data signals being input in parallel to the first wireless transmission device at a fixed rate, and the second data signal being input to the first wireless transmission device at a variable rate; and include, in the first frame, information relating to a number of multiplexed first data signals, 10 wherein the second wireless transmission device is configured to: separate, from the first frame, the first data signals, the second data signal, and the information relating to the number of multiplexed first data signals; multiplex a plurality of third data signals and a fourth data signal to 15 generate the second frame, the third data signals being input in parallel to the second wireless transmission device at a fixed rate, and the fourth data signal being input to the second wireless transmission device at a variable rate; and determine a number of multiplexed third data signals according to the number of multiplexed first data signals. 20

9. A method for controlling a wireless transmission device employing an adaptive modulation scheme, the wireless transmission device sending a first frame to an opposing device through a first wireless transmission path and receiving a second frame from the opposing device through a second wireless 25 transmission path, the second wireless transmission path having a frequency different from the first wireless transmission path, the method comprising: multiplexing a plurality of first data signals and a second data signal to generate the first frame, the first data signals being input in parallel at a fixed rate, and the second data signal being input at a variable rate; and 30 including, in the first frame, information relating to a number of multiplexed first data signals.

10. A method for controlling a wireless transmission device employing an adaptive modulation scheme, the wireless transmission device receiving a first 15 •f^i^A :3*? r »' ''•''^' I A%i 28' \ I Cno--"" \ ^ \I %>. / 3 ^ 2 5 HO^ frame from an opposing device through a first wireless transmission path and im transmitting a second frame to the opposing device through a second wireless transmission path, the second wireless transmission path having a frequency different from the first wireless transmission path, the method comprising: 5 separating, from the first frame, a plurality of first data signals, a second signal, and information relating to a number of multiplexed first data signals, the first data signals being input in parallel to the opposing device at a fixed rate, and the second data signal being input to the opposing device at a variable rate; multiplexing a plurality of third data signals and a fourth data signal to 10 generate the second frame, the third data signals being input in parallel to the wireless transmission device at a fixed rate, and the fourth data signal being input to the wireless transmission device at a variable rate; and determining a number of multiplexed third data signals according to the number of multiplexed first data signals.

DESCRIPTION
WIRELESS TRANSMISSION DEVICE, WIRELESS TRANSMISSION
SYSTEM, AND METHOD FOR CONTROLLING WIRELESS
TRANSMISSION DEVICE
5
Technical Field
[0001]
The present invention relates to a wireless transmission device, a wireless
transmission system, and a method for controlling a wireless transmission device,
10 and in particular, to a technique for multiplexing fixed rate signals and a variable
rate signal in one wireless transmission band for transmission.
Background Art
[0002]
15 FWA (Fixed Wireless Access) system is well known as a wireless
transmission system employing the above transmission technique. The FWA
system is generally composed of two opposing wireless transmission devices and
capable of providing a communication service between two distant points (e.g.,
between a subscriber located at an isolated island and a subscriber located at a
20 mountainous area) without laying cables and the like.
[0003]
To each wireless transmission device, fixed rate data signals (hereinafter
may be referred to as fixed rate signals) as the one specified in ITU-T
(International Telecommunication Union Telecommunication Standardization
25 Sector) G.703, for example, are input in parallel, and a variable rate data signal
(hereinafter may be referred to as a variable rate signal) as in Ethernet
(registered trademark) is also input. Each wireless transmission device
multiplexes a variable rate signal and a plurality of fixed rate signals, and
transmits the multiplexed signal to an opposing device through one wireless
30 transmission path.
[0004]
Incidentally, in recent years, the adaptive modulation scheme is often
employed by wireless transmission devices. This is because that the adaptive
modulation scheme enables both maximization of transmission capacity and
securing of minimum transmission capacity according to a state of a wireless
transmission path.
[0005]
Moreover, in many cases, the FDD (Frequency Division Duplex) scheme
5 is used together by wireless transmission devices. In the FDD scheme, different
frequencies are used for an uplink wireless transmission path and a downlink
wireless transmission path, and it is common that wireless transmission path
characteristics are different in the uplink wireless transmission path and the
downlink wireless transmission path.
10 [0006]
For this reason, a wireless transmission device employing both of the
adaptive modulation scheme and the FDD scheme may select different
modulation schemes for an uplink wireless transmission path and a downlink
wireless transmission path. In such a case, there has been a problem that, in a
15 symmetric transmission path, symmetric property between the uplink wireless
transmission path and the downlink wireless transmission path cannot be retained,
and in an asymmetric transmission path, a desired transmission ratio cannot be
maintained.
[0007]
20 As a technique to address this problem, Patent Literature 1, for example,
discloses a method capable of using the same modulation scheme in the opposing
wireless transmission devices at all times. To be more specific, in Patent
Literature 1, when modulation scheme differs between wireless transmission
devices due to a difference in characteristics of an uplink wireless transmission
25 path and a downlink wireless transmission path, control is performed such that
the modulation scheme is changed to a direction with a lower multiple value.
Citation List
Patent Literature
30 [0008]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2006-217663
Patent Literature 2: Japanese Unexamined Patent Application Publication No.
2010-171542
Summary of Invention
Technical Problem
[0009]
5 However, the present inventor has found out that above Patent Literature
1 has a problem in which efficiency of data transmission in a wireless
transmission band has not improved. This is because the modulation scheme is
changed to a direction with a lower multiple value, consequently disabling
selection of the modulation scheme to achieve the maximum transmission
10 capacity. In other words, above Patent Literature 1 compromises the advantages
of the adaptive modulation scheme (i.e., achieving both maximization of
transmission capacity and securing minimum transmission capacity).
[0010]
On the other hand, the present inventor has found another problem that, in
15 a wireless transmission system like FWA system, when modulation scheme
differs between wireless transmission devices, the number of fixed rate signals
that can be multiplexed in a wireless transmission band will be asymmetric,
consequently reducing efficiency of data transmission in the wireless
transmission band. When one wireless transmission device multiplexes more
20 fixed rate signals than another wireless transmission device, the other wireless
transmission device could receive redundant fixed rate signals. However, the
redundant fixed rate signals are not processed but are discarded. This is
because that the other wireless transmission device is unable to secure a band for
sending response signals (which are also fixed rate signals) to the redundant
25 fixed rate signals. In other words, one wireless transmission device multiplexes
redundant fixed rate signals in the wireless transmission band.
[0011]
Note that as a related technique. Patent Literature 2 discloses a system
that connects wireless transmission devices via a main wireless transmission path
30 and a standby wireless transmission path, and employs different modulation
schemes for the transmission paths to transmit fixed rate signals through the
transmission paths. However, the technique disclosed in Patent Literature 2
uses redundant wireless resources, running counter to the improvement in
efficiency of data transmission.
[0012]
Accordingly, an object of the present invention is to improve efficiency of
data transmission in a wireless transmission band under a condition in which
both adaptive modulation scheme and FDD scheme are employed, and fixed rate
5 signals and a variable rate signal are multiplex-transmitted.
Solution to Problem
[0013]
In order to achieve the above object, a first exemplary aspect of the
10 present invention is a wireless transmission device that includes: communication
means employing an adaptive modulation scheme for sending a first frame to an
opposing device through a first wireless transmission path, and receiving a
second frame from the opposing device through a second wireless transmission
path, the second wireless transmission path having a frequency different from the
15 first wireless transmission path; and multiplex means for multiplexing a plurality
of first data signals and a second data signal to generate the first frame, the first
data signals being input in parallel at a fixed rate, and the second data signal
being input at a variable rate. The multiplex means includes, in the first frame,
information relating to a number of multiplexed first data signals.
20 [0014]
A second exemplary aspect of the present invention is a wireless
transmission device that includes: communication means employing an adaptive
modulation scheme for receiving a first frame from an opposing device through a
first wireless transmission path, and sending a second frame to the opposing
25 device through a second wireless transmission path, the second wireless
transmission path having a frequency different from the first wireless
transmission path; separation means for separating, from the first frame, a
plurality of first data signals, a second data signal, and information relating to a
number of multiplexed first data signals, the first data signals being input in
30 parallel to the opposing device at a fixed rate, and the second data signal being
input to the opposing device at a variable rate; and multiplex means for
multiplexing a plurality of third data signals and a fourth data signal to generate
the second frame, the third data signals being input in parallel to the wireless
transmission device at a fixed rate, and the fourth data signal being input to the
wireless transmission device at a variable rate. The multiplex means determines
a number of multiplexed third data signals according to the number of
multiplexed first data signals.
[0015]
5 A third exemplary aspect of the present invention is a wireless
transmission system that includes: a first wireless transmission device employing
an adaptive modulation scheme that sends a first frame through a first wireless
transmission path and receives a second frame through a second wireless
transmission path, the second wireless transmission path having a frequency
10 different from the first wireless transmission path; and a second wireless
transmission device employing the adaptive modulation scheme that receives the
first frame from the first wireless transmission device through the first wireless
transmission path and transmits the second frame to the first wireless
transmission device through the second wireless transmission path. The first
15 wireless transmission device is configured to: multiplexes a plurality of first data
signals and a second data signal to generate the first frame, the first data signals
being input in parallel to the first wireless transmission device at a fixed rate,
and the second data signal being input to the first wireless transmission device at
a variable rate; and include, in the first frame, information relating to a number
20 of multiplexed first data signals. The second wireless transmission device is
configured to: separate, from the first frame, the first data signals, the second
data signal, and the information relating to the number of multiplexed first data
signals; multiplex a plurality of third data signals and a fourth data signal to
generate the second frame, the third data signals being input in parallel to the
25 second wireless transmission device at a fixed rate, and the fourth data signal
being input to the second wireless transmission device at a variable rate; and
determine a number of multiplexed third data signals according to the number of
multiplexed first data signals.
[0016]
30 A fourth exemplary aspect of the present invention is a method for
controlling a wireless transmission device employing an adaptive modulation
scheme that sends a first frame to an opposing device through a first wireless
transmission path and receives a second frame from the opposing device through
a second wireless transmission path, the second wireless transmission path
having a frequency different from the first wireless transmission path. The
method includes: multiplexing a plurality of first data signals and a second data
signal to generate the first frame, the first data signals being input in parallel at a
fixed rate, and the second data signal being input at a variable rate; and including,
5 in the first frame, information relating to a number of multiplexed first data
signals.
[0017]
A fifth exemplary aspect of the present invention is a method for
controlling a wireless transmission device employing an adaptive modulation
10 scheme that receives a first frame from an opposing device through a first
wireless transmission path and transmits a second frame to the opposing device
through a second wireless transmission path, the second wireless transmission
path having a frequency different from the first wireless transmission path. The
method includes: separating, from the first frame, a plurality of first data signals,
15 a second signal, and information relating to a number of multiplexed first data
signals, the first data signals being input in parallel to the opposing device at a
fixed rate, and the second data signal being input to the opposing device at a
variable rate; multiplexing a plurality of third data signals and a fourth data
signal to generate the second frame, the third data signals being input in parallel
20 to the wireless transmission device at a fixed rate, and the fourth data signal
being input to the wireless transmission device at a variable rate; and
determining a number of multiplexed third data signals according to the number
of multiplexed first data signals.
25 Advantageous Effects of Invention
[0018]
According to the present invention, it is possible to improve efficiency of
data transmission in a wireless transmission band under a condition in which
both adaptive modulation scheme and FDD scheme are employed, and fixed rate
30 signals and a variable rate signal are multiplex-transmitted.
Brief Description of Drawings
[0019]
Fig. 1 is a block diagram showing a configuration example of a wireless
8
transmission system according to a first exemplary embodiment of the present
invention;
Fig. 2 is a configuration example of a frame used in the wireless
transmission system according to the first exemplary embodiment of the present
5 invention;
Fig. 3 is a block diagram showing a configuration example of a wireless
transmission device according to the first exemplary embodiment of the present
invention;
Fig. 4 is a flowchart showing an operation example of the wireless
10 transmission device according to the first exemplary embodiment of the present
invention;
Fig. 5 is a first data transmission example in the wireless transmission
device according to the first exemplary embodiment of the present invention;
Fig. 6 is a second data transmission example in the wireless transmission
15 device according to the first exemplary embodiment of the present invention;
Fig. 7 is a third data transmission example in the wireless transmission
device according to the first exemplary embodiment of the present invention; and
Fig. 8 is a block diagram showing a configuration example of a wireless
transmission device according to a second exemplary embodiment of the present
20 invention.
Description of Embodiments
[0020]
Hereinafter, first and second exemplary embodiments of a wireless
25 transmission device according to the present invention and a wireless
transmission system to which the wireless transmission device is applied will be
explained with reference to Figs. 1 to 8. Note that in the drawings, identical or
similar components are denoted by identical or similar reference codes, and
repeated explanation will not be provided as appropriate for clarity of
30 explanation.
[0021]

As shown in Fig. 1, a wireless transmission system 1 according to this
exemplary embodiment includes two opposing wireless transmission devices 2_1
and 2_2 (hereinafter may be collectively referred to by a code 2). The wireless
transmission devices 2 employ adaptive modulation scheme. Moreover, the
wireless transmission devices 2 also employ FDD scheme.
[0022]
5 Among them, to the wireless transmission device 2_1 from outside, a
plurality of fixed rate signals FS1_1 to FSl_n (n is an integer of 2 or greater) are
input in parallel and a variable rate signal VS2 is input. The wireless
transmission device 2_1 multiplexes some fixed rate signals and a variable rate
signal to generate a wireless frame FRl.
10 [0023]
At this time, the wireless transmission device 2_1 includes, in the frame
FRl, information MN relating to the number of multiplexed fixed rate signals
(the information MN may be hereinafter referred to as multiplex number
information). The multiplex number information MN indicates the number of
15 fixed rate signals multiplexed in a frame. The frame may be configured as
shown in Fig. 2, for example. A frame FR shown in Fig. 2 includes an overhead
region 101 and a payload region 102. In this case, the wireless transmission
device 2 1 sets the multiplex number information MN to, for example, a reserve
region in the overhead region 101. Moreover, the wireless transmission device
20 2 1 sets fixed rate signals FS and a variable rate signal VS to the payload area
102.
[0024]
Then, the wireless transmission device 2 1 sends the frame FRl to the
wireless transmission device 2 2 through a wireless transmission path CHI.
25 [0025]
On the other hand, when the wireless transmission device 2_2 receives the
frame FRl, the wireless transmission device 2 2 separates the fixed rate signals,
the variable rate signal, and the multiplex number information MN from the
frame FRl. The wireless transmission device 2_2 outputs, to outside, the fixed
30 rate signals F S l l to FSl_n and the variable rate signal VS2 that are obtained in
the separation.
[0026]
To the wireless transmission device 2_2 from outside, a plurality of fixed
rate signals FS3_1 to FS3_n are input in parallel and a variable rate signal VS4 is
10
input. Note that the number "n" of fixed rate signals that are input to the
wireless transmission devices 2_1 and 2_2 may be different from each other.
The wireless transmission device 2_2 multiplexes some fixed rate signals and a
variable rate signal to generate a wireless frame FR2.
5 [0027]
At this time, the wireless transmission device 2_2 determines the number
of multiplexed fixed rate signals in the frame FR2 according to the multiplex
number information MN. To be more specific, the wireless transmission device
2_2 reduces or increases the number of fixed rate signals multiplexed in the
10 frame FR2 to be equalized to the number of fixed rate signals multiplexed in the
frame FRl.
[0028]
Then, the wireless transmission device 2_2 sends the frame FR2 to the
wireless transmission device 2 1 through a wireless transmission path CH2 to
15 which a frequency different from that of CHI is applied.
[0029]
When the wireless transmission device 2 1 receives the frame FR2, the
wireless transmission device 2_1 separates the fixed rate signals and the variable
rate signal from the frame FR2. The wireless transmission device 2_1 outputs,
20 to outside, the fixed rate signals FS3_1 to FS3_n and the variable rate signal VS4
that are obtained in the separation.
[0030]
As described above, in this exemplary embodiment, one wireless
transmission device indicates the number of multiplexed fixed rate signals, and
25 another wireless transmission device adjusts the number of multiplexed fixed
rate signals according to this indication.
[0031]
Therefore, even when the modulation scheme differs between the wireless
transmission devices due to a difference in characteristics between an uplink
30 wireless transmission path and a downlink wireless transmission path, it is
possible to make adjustment such that the number of multiplexed fixed rate
signals is symmetrical between the wireless transmission devices. In other
words, it is possible to avoid a situation such that a redundant fixed rate signal is
multiplexed in a wireless transmission band by one wireless transmission device
11
and discarded by the other wireless transmission device.
[0032]
Further, in this exemplary embodiment, different modulation schemes
may be applied to an uplink wireless transmission path and a downlink wireless
5 transmission path, thereby not compromising the advantages of the adaptive
modulation scheme unlike above Patent Literature 1.
[0033]
Hence, according to this exemplary embodiment, it is possible to greatly
improve efficiency of data transmission than in related techniques, under a
10 condition in which both the adaptive modulation scheme and the FDD scheme are
employed, and fixed rate signals and a variable rate signal are
multiplex-transmitted. Note that it is not essential to equalize the number of
multiplexed fixed rate signals between the wireless transmission devices. This
is because that the closer the numbers of multiplexed fixed rate signals between
15 the wireless transmission devices, the less the redundant usage of wireless
transmission band.
[0034]
Hereinafter, specific configuration example and operation example of the
wireless transmission device 2 which achieve the above-mentioned operation will
20 be explained in detail with reference to Figs. 3 to 7.
[0035]
As shown in Fig. 3, the wireless transmission device 2 includes a wireless
communication unit 10, a wireless frame multiplex unit 20, and a wireless frame
separation unit 30.
25 [0036]
Among them, the wireless communication unit 10 performs processing,
such as modulation processing, DA (Digital to Analog) conversion and frequency
conversion, for a transmission frame FRt input from the wireless frame multiplex
unit 20, thereby outputting the transmission frame FRt as a wireless signal via an
30 antenna 11. Moreover, the wireless communication unit 10 performs processing,
such as frequency conversion, AD (Analog to Digital) conversion and
demodulation processing, for a wireless signal received via the antenna 11, and
outputs a reception frame FRr obtained accordingly to the wireless frame
separation unit 30. Further, the wireless communication unit 10 includes an
12
adaptive modulation control unit 12, as indicated by the dotted line in Fig. 3.
The adaptive modulation control unit 12 performs control to select a modulation
scheme and a demodulation scheme according to a state of a wireless
transmission path. To be more specific, the adaptive modulation control unit 12
5 calculates transmission quality of the wireless transmission path that fluctuates
due to, for example, an influence of waveform attenuation by rain and multipath
fading, and dynamically changes a modulation scheme and a demodulation
scheme according to the transmission quality.
[0037]
10 The wireless frame multiplex unit 20 includes "n" units of fixed rate
signal input units 2 1 1 to 21_n, a variable rate signal input unit 22, a multiplex
unit 23, and a multiplex control unit 24.
[0038]
Each of the fixed rate signal input units 21_1 to 21_n includes an input
15 terminal 25 and a transmission buffer 26. Each of "n" units of transmission
fixed rate signals FSt_l to F S t n (hereinafter may be collectively referred to by a
code FSt) is stored to the transmission buffer 26 through the input terminal 25.
[0039]
The variable rate signal input unit 22 includes an input terminal 27 and a
20 transmission buffer 28. A transmission variable rate signal VSt is stored to the
transmission buffer 28 through the input terminal 27.
[0040]
The multiplex unit 23 multiplexes the fixed rate signals FSt and the
variable rate signal VSt in the frame FRt according to transmission multiplex
25 number information MNt that is input from the multiplex control unit 24, and
outputs the frame FRt to the wireless communication unit 10. At this time, the
multiplex unit 23 calculates transmission capacity of signals (a length of the
payload region 102 shown in Fig. 2) according to the modulation scheme selected
by the wireless communication unit 10. Moreover, the multiplex unit 23 reads
30 out, from the transmission buffers 26 in the fixed rate signal input units 21_1 to
21_n, the fixed rate signals FSt for the number indicated by the multiplex number
information MNt in, for example, ascending or descending order of signal
numbers " 1 " to "n", and sets the fixed rate signals FSt to a part of the payload
region 102. Further, the multiplex unit 23 reads out the variable rate signal VSt
13
from the transmission buffer 28 in the variable rate signal input unit 22, and sets
the variable rate signal VSt to the remaining payload region 102. Furthermore,
the multiplex unit 23 sets the multiplex number information MNt to the overhead
region 101.
5 [0041]
The multiplex control unit 24 determines the transmission multiplex
number information MNt according to reception multiplex number information
MNr that is input from the wireless frame separation unit 30. The reception
multiplex number information MNr is set by an opposing device and indicates the
10 number of fixed rate signals multiplexed in the reception frame FRr. The
multiplex control unit 24 equalizes the number of fixed rate signals to be
multiplexed in the transmission frame FRt to the number of fixed rate signals
multiplexed in the reception frame FRr. Moreover, the multiplex control unit 24
outputs, to the multiplex unit 23, the equalized number as the transmission
15 multiplex number information MNt.
[0042]
The wireless frame separation unit 30 includes a separation unit 31, "n"
units of fixed rate signal output units 32_1 to 32_n, and a variable rate signal
output unit 33.
20 [0043]
The separation unit 31 extracts, from the reception frame FRr, reception
fixed rate signals FSr_l to FSr_n (hereinafter may be collectively referred to by
a code FSr), a reception variable rate signal VSr, and the reception multiplex
number information MNr. At this time, the separation unit 31 outputs the
25 reception fixed rate signals FSr_l to F S r n to the fixed rate signal output units
3 2 1 to 32_n, respectively. Further, the separation unit 31 outputs the reception
variable rate signal VSr to the variable rate signal output unit 33. Furthermore,
the separation unit 31 outputs the reception multiplex number information MNr
to the multiplex control unit 24 in the wireless frame multiplex unit 20.
30 [0044]
Each of the fixed rate signal output units 32_1 to 32_n includes a
reception buffer 34 and an output terminal 35. Each of the reception fixed rate
signals FSr_l to FSr_n is stored to the reception buffer 34 once, and then output
to outside through the output terminal 35.
14
• [0045]
The variable rate signal output unit 33 includes a reception buffer 36 and
an output terminal 37. The reception variable rate signal VSr is stored to the
reception buffer 36 once, and then output to outside through the output terminal
5 37.
[0046]
Next, the specific operation example of the wireless transmission device 2
will be explained with reference to Figs. 4 to 7.
[0047]
10 As shown in Fig. 4, the multiplex control unit 24 in the wireless
transmission device 2 compares the number indicated by the transmission
multiplex number information MNt (the current number of fixed rate signals
multiplexed in the transmission frame FRt) and the number indicated by the
reception multiplex number information MNr every time the reception multiplex
15 number information MNr is extracted by the separation unit 31. Note that in the
subsequent explanation, the number indicated by the transmission multiplex
number information MNt may be referred to as a transmission multiplex number
and may be referred by the same code MNt. Similarly, the number indicated by
the reception multiplex number information MNr may be referred to as a
20 reception multiplex number and may be referred by the same code MNr.
[0048]
As a result, when "the transmission multiplex number MNt = the receiving
multiplex number MNr" is satisfied (Step SI), the multiplex control unit 24 does
not change the transmission multiplex number MNt.
25 [0049]
Thus, as shown in Fig. 5, the state is maintained in which the number of
the fixed rate signals FSt multiplexed in the transmission frame FRt is equalized
to the number of the fixed rate signals FSr multiplexed in the reception frame
FRr.
30 [0050]
Meanwhile, when the modulation scheme of the wireless transmission
device 2 and the opposing device is not the same, consequently satisfying "the
transmission multiplex number MNt > the reception multiplex number MNr"
(Step S2), processing indicated by Steps S3 and S4 is executed by cooperation of
15
the multiplex control unit 24 and the multiplex unit 23.
[0051]
Assume that as shown in Fig. 6, the wireless transmission device 2 sends
a frame FRt_l and receives a frame F R r l at a certain timing. Further, assume
5 that more fixed rate signals FSt are multiplexed in the transmission frame F R tl
than fixed rate signals FSr multiplexed in the reception frame F R r l . As
explained above, a redundant fixed rate signal is likely to be discarded by the
opposing device (Step S l l ).
[0052]
10 Therefore, the multiplex control unit 24 reduces the transmission
multiplex number MNt so as to equalize the transmission multiplex number MNt
to the reception multiplex number MNr (Step S3). Then, the multiplex control
unit 24 notifies the multiplex unit 23 of the updated transmission multiplex
number MNt. The multiplex unit 23 multiplexes the fixed rate signals FSt in a
15 frame FRt_2 to be transmitted next according to the updated transmission
multiplex number MNt.
[0053]
Thus, as shown in Fig. 6, the number of the fixed rate signals FSt
multiplexed in the transmission frame FRt_2 is equalized to the number of the
20 fixed rate signals FSr multiplexed in a frame FRr_2 that is received next from the
opposing device.
[0054]
Moreover, the multiplex unit 23 allocates a vacant region in the payload
region 102 generated by the reduction in the transmission multiplex number MNt
25 to multiplexing of the transmission variable rate signal VSt (Step S4).
[0055]
This makes it possible to improve transmission efficiency of the variable
rate signal, thereby optimizing efficiency of data transmission in a wireless
transmission band.
30 [0056]
On the other hand, in the above Step S2, when "the transmission multiplex
number MNt < the reception multiplex number MNr" is satisfied, that is, as
shown in Fig. 7, when a transmission band for the fixed rate signals FSt in the
transmission frame FRt 1 is insufficient relative to a transmission band for the
16
fixed rate signals FSr in the reception frame FRr_l (Step S21), the multiplex
control unit 24 increases the transmission multiplex number MNt to be equalized
to the reception multiplex number MNr to thereby reduce the transmission band
for the transmission variable rate signals VSt (Step S5).
5 [0057]
Then, the multiplex control unit 24 notifies the multiplex unit 23 of the
updated transmission multiplex number MNt. The multiplex unit 23 allocates a
vacant region in the payload region 102 generated by the reduction in the
transmission band for the transmission variable rate signal VSt to multiplexing of
10 the fixed rate signals FSt (Step S6).
[0058]
Thus, as shown in Fig. 7, the number of the fixed rate signals FSt
multiplexed in the transmission frame FRt_2 is equalized to the number of the
fixed rate signals FSr multiplexed in the reception frame FRr_2.
15 [0059]

A wireless transmission system according to this exemplary embodiment
can be configured in a similar manner to the above first exemplary embodiment.
Meanwhile, a wireless transmission device according to this exemplary
20 embodiment differs from that in the above-mentioned first exemplary
embodiment in that the wireless transmission device is configured as shown in
Fig. 8.
[0060]
Specifically, in a wireless transmission device 2a shown in Fig. 8, a
25 cross-connect unit 29 is further provided in the wireless frame multiplex unit 20.
The cross-connect unit 29 performs cross-connect processing for transmission
fixed rate signals FSt_l to FSt_n, which are respectively read out from the fixed
rate signal input units 21_1 to 21_n, according to transmission cross-connect
information INFt that is input from the multiplex control unit 24, and outputs the
30 transmission fixed rate signals FSt_l to FSt_n to the multiplex unit 23.
[0061]
Priorities of the respective transmission fixed rate signals F S t l to F S tn
are set to the transmission cross-connect information INFt. The cross-connect
unit 29 reads higher-priority transmission fixed rate signals preferentially to
17
other transmission fixed rate signals, and transfers the read fixed rate signals to
the multiplex unit 23.
[0062]
Thus, even when the multiplex unit 23 multiplexes the fixed rate signals
5 FSt for the number indicated by the transmission multiplex number information
MNt in the transmission frame FRt in ascending or descending order of the signal
numbers " 1 " to "n" as explained in the above first exemplary embodiment, it is
possible to guarantee a band for the higher-priority fixed rate signals.
[0063]
10 In addition, in this exemplary embodiment, a cross-connect unit 38 may
further be provided in the wireless frame separation unit 30, as indicated by the
dotted line in Fig. 8. In such a case, the cross-connect unit 38 performs
cross-connect processing for the reception fixed rate signals FSr_l to F S rn
according to reception cross-connect information INFr that is input from the
15 multiplex control unit 24. Specifically, output destinations of the respective
reception fixed rate signals F S r l to FSr_n are set to the reception cross-connect
information INFr. The cross-connect unit 38 transfers the reception fixed rate
signals FSr to appropriate fixed rate signal output units according to this setting.
[0064]
20 Note that it is obvious that the present invention is not limited to the
above exemplary embodiments but various modifications can be made by a
person skilled in the art based on description in the claims.
[0065]
The present application claims priority rights of and is based on Japanese
25 Patent Application No. 2011-122042 filed on May 31, 2011 in the Japanese
Patent Office, the entire contents of which are hereby incorporated by reference.
Industrial Applicability
[0066]
30 The present invention is applied to a wireless transmission device, a
wireless transmission system, and a method for controlling a wireless
transmission device, and particularly to usage of multiplexing fixed rate signals
and a variable rate signal in one wireless transmission band to be transmitted.
[0067]
18
The whole or part of the exemplary embodiments disclosed above can be
described as, but not limited to, the following supplementary notes.
[0068]
(Supplementary note 1)
5 A wireless transmission device comprising:
communication means employing an adaptive modulation scheme for
sending a first frame to an opposing device through a first wireless transmission
path, and receiving a second frame from the opposing device through a second
wireless transmission path, the second wireless transmission path having a
10 frequency different from the first wireless transmission path; and
multiplex means for multiplexing a plurality of first data signals and a
second data signal to generate the first frame, the first data signals being input in
parallel at a fixed rate, and the second data signal being input at a variable rate,
wherein the'multiplex means includes, in the first frame, information
15 relating to a number of multiplexed first data signals.
[0069]
(Supplementary note 2)
The wireless transmission device according to Supplementary note 1,
further comprising:
20 separation means for separating, from the second frame, a plurality of
third data signals, a fourth data signal, and information relating to a number of
multiplexed third data signals, the third data signals being input in parallel to the
opposing device at a fixed rate, and the fourth data signal being input to the
opposing device at a variable rate,
25 wherein the multiplex means determines the number of multiplexed first
data signals according to the number of multiplexed third data signals.
[0070]
(Supplementary note 3)
The wireless transmission device according to Supplementary note 2,
30 wherein the multiplex means equalizes the number of multiplexed first data
signals to the number of multiplexed third data signals.
[0071]
(Supplementary note 4)
The wireless transmission device according to Supplementary note 2 or 3,
19
wherein when the multiplex means determines to reduce the number of
multiplexed first data signals, the multiplex means allocates a vacant region in
the first frame generated by reduction to multiplexing of the second data signal.
[0072]
5 (Supplementary note 5)
The wireless transmission device according to any one of Supplementary
notes 1 to 4, wherein the multiplex means selects a data signal to be multiplexed
in the first frame from the first data signals according to priorities of the first
data signals.
10 [0073]
(Supplementary note 6)
A wireless transmission device comprising:
communication means employing an adaptive modulation scheme for
receiving a first frame from an opposing device through a first wireless
15 transmission path, and sending a second frame to the opposing device through a
second wireless transmission path, the second wireless transmission path having
a frequency different from the first wireless transmission path;
separation means for separating, from the first frame, a plurality of first
data signals, a second data signal, and information relating to a number of
20 multiplexed first data signals, the first data signals being input in parallel to the
opposing device at a fixed rate, and the second data signal being input to the
opposing device at a variable rate; and
multiplex means for multiplexing a plurality of third data signals and a
fourth data signal to generate the second frame, the third data signals being input
25 in parallel to the wireless transmission device at a fixed rate, and the fourth data
signal being input to the wireless transmission device at a variable rate,
wherein the multiplex means determines a number of multiplexed third
data signals according to the number of multiplexed first data signals.
[0074]
30 (Supplementary note 7)
The wireless transmission device according to Supplementary note 6,
wherein the multiplex means equalizes the number of multiplexed third data
signals to the number of multiplexed first data signals.
[0075]
20
(Supplementary note 8)
The wireless transmission device according to Supplementary note 6 or 7,
wherein when the multiplex means determines to reduce the number of
multiplexed third data signals, the multiplex means allocates a vacant region in
5 the second frame generated by reduction to multiplexing of the fourth data
signal.
[0076]
(Supplementary note 9)
A wireless transmission system comprising:
10 a first wireless transmission device employing an adaptive modulation
scheme that sends a first frame through a first wireless transmission path and
receives a second frame through a second wireless transmission path, the second
wireless transmission path having a frequency different from the first wireless
transmission path; and
15 a second wireless transmission device employing the adaptive modulation
scheme that receives the first frame from the first wireless transmission device
through the first wireless transmission path and transmits the second frame to the
first wireless transmission device through the second wireless transmission path,
wherein the first wireless transmission device is configured to:
20 multiplex a plurality of first data signals and a second data signal to
generate the first frame, the first data signals being input in parallel to the first
wireless transmission device at a fixed rate, and the second data signal being
input to the first wireless transmission device at a variable rate; and
include, in the first frame, information relating to a number of
25 multiplexed first data signals,
wherein the second wireless transmission device is configured to:
separate, from the first frame, the first data signals, the second data
signal, and the information relating to the number of multiplexed first data
signals;
30 multiplex a plurality of third data signals and a fourth data signal to
generate the second frame, the third data signals being input in parallel to the
second wireless transmission device at a fixed rate, and the fourth data signal
being input to the second wireless transmission device at a variable rate; and
determine a number of multiplexed third data signals according to the
21
number of multiplexed first data signals.
[0077]
(Supplementary note 10)
A method for controlling a wireless transmission device employing an
5 adaptive modulation scheme, the wireless transmission device sending a first
frame to an opposing device through a first wireless transmission path and
receiving a second frame from the opposing device through a second wireless
transmission path, the second wireless transmission path having a frequency
different from the first wireless transmission path, the method comprising:
10 multiplexing a plurality of first data signals and a second data signal to
generate the first frame, the first data signals being input in parallel at a fixed
rate, and the second data signal being input at a variable rate; and
including, in the first frame, information relating to a number of
multiplexed first data signals.
15 [0078]
(Supplementary note 11)
The method according to Supplementary note 10, further comprising:
separating, from the second frame, a plurality of third data signals, a
fourth data signal, and information relating to a number of multiplexed third data
20 signals, the third data signals being input in parallel to the opposing device at a
fixed rate, and the fourth data signal being input to the opposing device at a
variable rate,
wherein the number of multiplexed first data signals is determined
according to the number of multiplexed third data signals.
25 [0079]
(Supplementary note 12)
The method according to Supplementary note 11, wherein the number of
multiplexed first data signals is equalized to the number of multiplexed third
data signals.
30 [0080]
(Supplementary note 13)
The method according to Supplementary note 11 or 12, further
comprising:
allocating, when it is determined to reduce the number of multiplexed
22
first data signals, a vacant region in the first frame generated by reduction to
multiplexing of the second data signal.
[0081]
(Supplementary note 14)
5 The method according to any one of Supplementary notes 10 to 13,
wherein a data signal to be multiplexed in the first frame is selected from the
first data signals according to priorities of the first data signals.
[0082]
(Supplementary note 15)
10 A method for controlling a wireless transmission device employing an
adaptive modulation scheme, the wireless transmission device receiving a first
frame from an opposing device through a first wireless transmission path and
transmitting a second frame to the opposing device through a second wireless
transmission path, the second wireless transmission path having a frequency
15 different from the first wireless transmission path, the method comprising:
separating, from the first frame, a plurality of first data signals, a second
signal, and information relating to a number of multiplexed first data signals, the
first data signals being input in parallel to the opposing device at a fixed rate,
and the second data signal being input to the opposing device at a variable rate;
20 multiplexing a plurality of third data signals and a fourth data signal to
generate the second frame, the third data signals being input in parallel to the
wireless transmission device at a fixed rate, and the fourth data signal being
input to the wireless transmission device at a variable rate; and
determining a number of multiplexed third data signals according to the
25 number of multiplexed first data signals.
[0083]
(Supplementary note 16)
The method according to Supplementary note 15, wherein the number of
multiplexed third data signals is equalized to the number of multiplexed first
30 data signals.
[0084]
(Supplementary note 17)
The method according to Supplementary note 15 or 16, further
comprising:
23
allocating, when it is determined to reduce the number of multiplexed
third data signals, a vacant region in the second frame generated by reduction to
multiplexing of the fourth data signal.
5 Reference Signs List
[0085]
1 WIRELESS TRANSMISSION SYSTEM
2, 2_1, 2_2, 2a WIRELESS TRANSMISSION DEVICE
10 WIRELESS COMMUNICATION UNIT
10 11 ANTENNA
12 ADAPTIVE MODULATION CONTROL UNIT
20 WIRELESS FRAME MULTIPLEX UNIT
21_l-21_n FIXED RATE SIGNAL INPUT UNIT
22 VARIABLE RATE SIGNAL INPUT UNIT
15 23 MULTIPLEX UNIT
24 MULTIPLEX CONTROL UNIT
25, 27 INPUT TERMINAL
26, 28 TRANSMISSION BUFFER
29, 38 CROSS-CONNECT UNIT
20 30 WIRELESS FRAME SEPERATION UNIT
31 SEPARATION UNIT
32_l-32_n FIXED RATE SIGNAL OUTPUT UNIT
33 VARIABLE RATE SIGNAL OUTPUT UNIT
34, 36 RECEPTION BUFFER
25 35, 37 OUTPUT TERMINAL
101 OVERHEAD REGION
102 PAYLOAD REGION
CHI, CH2 WIRELESS TRANSMISSION PATH
FR, FRl, FR2 WIRELESS FRAME
30 FRr, FRr_l, FRr_2 RECEPTION FRAME
FRt, FRt_l, FRt_2 TRANSMISSION FRAME
FS, FSl_l-FSl_n, FS3_l-FS3_n FIXED RATE SIGNAL
FSr, FSr_l-FSr_n RECEPTION FIXED RATE SIGNAL
FSt, FSt_l-FSt n TRANSMISSION FIXED RATE SIGNAL
24
INFr RECEPTION CROSS-CONNECT INFORMATION
INFt TRANSMISSION CROSS-CONNECT INFORMATION
MN MULTIPLEXING NUMBER (INFORMATION)
MNr RECEPTION MULTIPLEXING NUMBER (INFORMATION)
MNt TRANSMISSION MULTIPLEXING NUMBER (INFORMATION)
VS, VS2, VS4 VARIABLE RATE SIGNAL
VSr RECEPTION VARIABLE RATE SIGNAL
VSt TRANSMISSION VARIABLE RATE SIGNAL

WE CLAIM: % I 1 \^ ( «• ' an 6
5 ^0^ ^'^^^
1. A wireless transmission device comprising:
communication means employing an adaptive modulation scheme for
5 sending a first frame to an opposing device through a first wireless transmission
path, and receiving a second frame from the opposing device through a second
wireless transmission path, the second wireless transmission path having a
frequency different from the first wireless transmission path; and
multiplex means for multiplexing a plurality of first data signals and a
10 second data signal to generate the first frame, the first data signals being input in
parallel at a fixed rate, and the second data signal being input at a variable rate,
wherein the multiplex means includes, in the first frame, information
relating to a number of multiplexed first data signals.
15 2. The wireless transmission device according to Claim 1, further
comprising:
separation means for separating, from the second frame, a plurality of
third data signals, a fourth data signal, and information relating to a number of
multiplexed third data signals, the third data signals being input in parallel to the
20 opposing device at a fixed rate, and the fourth data signal being input to the
opposing device at a variable rate,
wherein the multiplex means determines the number of multiplexed first
data signals according to the number of multiplexed third data signals.
25 3. The wireless transmission device according to Claim 2, wherein the
multiplex means equalizes the number of multiplexed first data signals to the
number of multiplexed third data signals.
4. The wireless transmission device according to Claim 2 or 3, wherein
30 when the multiplex means determines to reduce the number of multiplexed first
data signals, the multiplex means allocates a vacant region in the first frame
generated by reduction to multiplexing of the second data signal.
#\5'
5. The wireless transmission device according to any one of Claims 1 to 4,
wherein the multiplex means selects a data signal to be multiplexed in the first
frame from the first data signals according to priorities of the first data signals.
5 6. A wireless transmission device comprising:
communication means employing an adaptive modulation scheme for
receiving a first frame from an opposing device through a first wireless
transmission path, and sending a second frame to the opposing device through a
second wireless transmission path, the second wireless transmission path having
10 a frequency different from the first wireless transmission path;
separation means for separating, from the first frame, a plurality of first
data signals, a second data signal, and information relating to a number of
multiplexed first data signals, the first data signals being input in parallel to the
opposing device at a fixed rate, and the second data signal being input to the
15 opposing device at a variable rate; and
multiplex means for multiplexing a plurality of third data signals and a
fourth data signal to generate the second frame, the third data signals being input
in parallel to the wireless transmission device at a fixed rate, and the fourth data
signal being input to the wireless transmission device at a variable rate,
20 wherein the multiplex means determines a number of multiplexed third
data signals according to the number of multiplexed first data signals.
7. The wireless transmission device according to Claim 6, wherein the
multiplex means equalizes the number of multiplexed third data signals to the
25 number of multiplexed first data signals.
8. A wireless transmission system comprising:
a first wireless transmission device employing an adaptive modulation
scheme that sends a first frame through a first wireless transmission path and
30 receives a second frame through a second wireless transmission path, the second
wireless transmission path having a frequency different from the first wireless
transmission path; and
a second wireless transmission device employing the adaptive modulation
scheme that receives the first frame from the first wireless transmission device
\5:
through the first wireless transmission path and transmits the second frame to the
first wireless transmission device through the second wireless transmission path,
wherein the first wireless transmission device is configured to:
multiplex a plurality of first data signals and a second data signal to
5 generate the first frame, the first data signals being input in parallel to the first
wireless transmission device at a fixed rate, and the second data signal being
input to the first wireless transmission device at a variable rate; and
include, in the first frame, information relating to a number of
multiplexed first data signals,
10 wherein the second wireless transmission device is configured to:
separate, from the first frame, the first data signals, the second data
signal, and the information relating to the number of multiplexed first data
signals;
multiplex a plurality of third data signals and a fourth data signal to
15 generate the second frame, the third data signals being input in parallel to the
second wireless transmission device at a fixed rate, and the fourth data signal
being input to the second wireless transmission device at a variable rate; and
determine a number of multiplexed third data signals according to the
number of multiplexed first data signals.
20
9. A method for controlling a wireless transmission device employing an
adaptive modulation scheme, the wireless transmission device sending a first
frame to an opposing device through a first wireless transmission path and
receiving a second frame from the opposing device through a second wireless
25 transmission path, the second wireless transmission path having a frequency
different from the first wireless transmission path, the method comprising:
multiplexing a plurality of first data signals and a second data signal to
generate the first frame, the first data signals being input in parallel at a fixed
rate, and the second data signal being input at a variable rate; and
30 including, in the first frame, information relating to a number of
multiplexed first data signals.
10. A method for controlling a wireless transmission device employing an
adaptive modulation scheme, the wireless transmission device receiving a first
15
•f^i^A :3*? r »' ''•''^' I A%i
28' \ I Cno--"" \ ^ \I %>. / 3 ^
2 5 HO^
frame from an opposing device through a first wireless transmission path and
im
transmitting a second frame to the opposing device through a second wireless
transmission path, the second wireless transmission path having a frequency
different from the first wireless transmission path, the method comprising:
5 separating, from the first frame, a plurality of first data signals, a second
signal, and information relating to a number of multiplexed first data signals, the
first data signals being input in parallel to the opposing device at a fixed rate,
and the second data signal being input to the opposing device at a variable rate;
multiplexing a plurality of third data signals and a fourth data signal to
10 generate the second frame, the third data signals being input in parallel to the
wireless transmission device at a fixed rate, and the fourth data signal being
input to the wireless transmission device at a variable rate; and
determining a number of multiplexed third data signals according to the
number of multiplexed first data signals.