Title of Invention

A COMMUNICATIONS APPARATUS AND A METHOD IN A COMMUNICATIONS SYSTEM FOR EXCHANGE OF INFORMATION BETWEEN COMMUNICATIONS APPARATUSES

Abstract The invention relates to a communications system for communications by a multicarrier transmission mode between a plurality of communications apparatuses (10, 20) wherein an overall frequency band assigned to the communications system is divided into a plurality of frequency bands each having a constant bandwidth (for example band 1 to band 4) and a specific band (for example band 1) among these divided bands is used to transmit used frequency band information and thereby determine the assignment of the remaining bands (band 2 to band 4) to be used between said communications apparatuses. Here, the specific band is defined as a main band for transmitting control channel information including said used frequency band information and also data channel information. The main band may also be added with an extension band for transmitting further data channel information. Further, the main band and extension band can be changed in the frequency band used along with time or can be changed in the number thereof. Both of the main band and the extension bands are preferably used by multiplexing by some of communications apparatuses.
Full Text

DESCRIPTION
TECHNICAL FIELD
The present invention relates to a.
communications system for exchange of information (data)
between communications apparatuses by a multicarrier
transmission mode by a series of subcarriers, more
particularly relates to a communications apparatus
accommodated in that communications system.
BACKGROUND ART
A most preferred example of the above
communications system discussed in the present invention
is a mobile communications system. The following
explanation will be made by taking as an example this
mobile communications system. Accordingly, if according
to this example, the communications apparatus is a (i)
base station (or a higher base station controller
thereof) and/or a (ii) mobile station (including a mobile
terminal such as a PDA). Note that for convenience, in
the later explanation, the former (i) will be referred to
as the "base station" and the latter (ii) will be simply
referred to as the "terminal" in some cases. Note that,
as will be clear in the later explanation, the present
invention can be substantially equivalently applied to
not only the above base station, but also the above
terminal. It is not particularly necessary to
differentiate between the two.
In a mobile communications system, securing a
desired transmission rate for a user is a major issue in
providing it with service. On the other hand, usually the
used frequency band used by the mobile communications
system is fixed for each system. Therefore, even if
employing user multiplexing etc., the maximum
transmission rate thereof ends up being restricted. For

this reason, the method of flexibly changing the used
frequency band in accordance with the required
transmission rate is being studied.
Further, when considered by the mobile
communications system as a whole, the state of usage
differs for each used frequency band. Sometimes a band is
not used at all. For this reason, from the viewpoint of
the effective utilization of the frequency, it has been
studied to make the used frequency band variable.
Under this situation, technology of making the
used frequency band variable in an MC (Multi-Carrier)-
CDMA (Code Division Multiple Access) or OFDM (Orthogonal
Frequency Division Multiplex) or other multicarrier
transmission mobile communications system has been
proposed. For example, the methods disclosed in the
following four Patent Documents 1 to 4 are proposed.
Details thereof will be explained later with reference to
the drawings, but these may be summarized as follows:
1) A "multiple connection method and apparatus"
disclosed in Patent Document 1 is characterized by
dividing a series of subcarriers so as to freely assign
used frequency bands to users.
2) A "mobile station, base station, and mobile
communications network" disclosed in Patent Document 2
are characterized in that a subcarrier band dedicated to
transmission of control signals is set in the
communications network.
3) A "channel allocation method" disclosed in
Patent Document 3 is characterized by changing the number
of subcarriers in the series of subcarriers in accordance
with length of the communications distance between the
base station and the mobile station.
4) A "wireless transmission apparatus and
wireless communications method" disclosed in Patent
Document 4 is characterized by changing the bandwidth of
each subcarrier in the series of subcarriers to make the
bandwidth of the used frequency band variable.

[Patent Document 1] Japanese Patent Publication
(A) No. 9-205411
[Patent Document 2] Japanese Patent Publication (A)
No. 2003-264524
[Patent Document 3] Japanese Patent Publication (A)
No. 2004-21476
[Patent Document 4] Japanese Patent Publication (A)
No. 2002-330467
DISCLOSURE OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
The prior arts based on the above four Patent
Documents 1 to 4 involve the following problems:
1) In Patent Document 1 (Japanese Patent
Publication (A) No. 9-205411), information on the used
subcarrier is not transmitted, therefore the reception
side must receive all subcarriers and decode them. This
is inefficient.
2) In Patent Document 2 (Japanese Patent
Publication (A) No. 2003-264524), information on the used
subcarrier is transmitted, but it is necessary to
receive, demodulate, and decode a common control channel
for transmitting this subcarrier information.
Further, when multiplexing users, the
information needed by the user must be extracted from
data transmitted over the common control channel.
Further, information directed to each user is contained
in that common control channel, therefore the bandwidth
might become insufficient at a low transmission rate.
Furthermore, the common control channel is common to all
users, therefore changing the used subcarrier will end up
having an effect on all users. Accordingly, the
subcarrier of that common control channel cannot be
easily changed.
3) In Patent Document 3 (Japanese Patent
Publication (A) No. 2004-214746), the bandwidth of the
data channel is made variable, but the common control
channel still uses a fixed frequency band common to all

users, so there is the same problem as that of Patent
Document 2.
4) In Patent Document 4 (Japanese Patent
Publication (A) No. 2002-330467), when considering the
use of user multiplexing, in order to suppress
interference due to the transmissions for many users, it
is necessary to further perform code multiplexing among
users. However, if the bandwidths of the subcarriers
become different among users, the orthogonality of codes
will be deteriorated and will end up becoming a cause of
interference.
In order to prevent this interference, where a
certain user changes the bandwidth of the subcarrier, the
other users must also change the bandwidths of the
subcarriers to match with that. As a result, the
bandwidths of the subcarriers are broadened due to the
user in a poor transmission situation, so the
transmission efficiency is lowered. Accordingly, there is
the inconvenience that changing the bandwidth of the
subcarrier sometimes will not be an effective means.
Accordingly, in consideration with the above
problems, an object of the present invention is to
provide a communications system (mobile communications
system) able to freely and easily extend, reduce, or
change the used frequency band of each user within the
overall frequency band allocated to the communications
system and preventing the above extension, reduction, or
change from having an effect on other users, more
particularly a communications apparatus (base station
and/or terminal) for this purpose.
DISCLOSURE OF THE INVENTION
According to the present invention, as will be
explained in detail later by using the drawings, a
specific frequency band is first set from among a
plurality of frequency bands obtaining by dividing the
overall frequency band allocated to the communications
system. Then, that specific frequency band is used to

transmit "used frequency band information" determining
which of the remaining frequency bands is to be used
between communications apparatuses from one
communications apparatus to another communications
apparatus. Further, that specific frequency band is set
as a "main band" in the above overall frequency band.
This main band transmits the above "used frequency band
information" plus "data information (user data)".
Further, among the above plurality of frequency bands, at
least one frequency band set from among the frequency
bands other than the above "main band" is defined as an
"extension band". This extension band is mainly used for
transmitting further data information and can deal with
an increase of amount of data. Accordingly, this
extension band is set according to need. However, the
above main band is always set at the time of
establishment of a wireless channel. In addition, this
main band transmits not only the above "used frequency
band information", but also the inherent "data
information" (user data) within a range permitted by the
transmission capacity. Further, this main band can
include also general "control information" (user control
information). Due to this, the above problems are solved.
BRIEF DESCRIPTION OF THE ACCOMPANYIN DRAWINGS
FIG. 1 is a view showing the basic
configuration of a communications apparatus (transmission
side) according to the present invention.
FIG. 2 is a view showing the basic configuration of
a communications apparatus (reception side) according to
the present invention.
FIG. 3 is a view showing a concrete example of a
communications apparatus (transmission side) 10 according
to the present invention.
FIG. 4 is a view showing a concrete example of a
communications apparatus (reception side) 20 according to
the present invention.
FIG. 5 is a view showing a modification of the

communications apparatus (transmission side) 10 according
to the present invention.
FIG. 6 is a view showing a modification of the
communications apparatus (reception side) 20 according to
the present invention.
FIG. 7 is a view showing another modification of the
communications apparatus (transmission side) 10 according
to the present invention.
FIG. 8 is a view showing another modification of the
communications apparatus (reception side) 20 according to
the present invention.
FIG. 9 is a view showing the pattern of frequency
division in a communications system.
FIG. 10 is a view showing a state of selecting one
"main band" and "extension band" each.
FIG. 11 is a view showing a first example of a mode
of allocation of main bands for a plurality of users.
FIG. 12 is a view showing a second example of a mode
of allocation of main bands for a plurality of users.
FIG. 13 is a flow chart showing an example of
dynamically changing the frequency band of a main band.
FIG. 14A and FIG. 14B are views showing an example
of the hardware configuration on the transmission side of
pilot signals.
FIG. 15A and FIG. 15B are views showing an example
of the hardware configuration on a return side of
response (CQI) information to a pilot signal.
FIG. 16 is a view showing a first example of
multiplexing of the pilot signals.
FIG. 17 is a view showing a second example of
multiplexing of the pilot signals.
FIG. 18 is a view showing an example of the dynamic
change of the main band for easy understanding.
FIG. 19 is a flow chart showing a first example of
introduction and allocation of an extension band.
FIG. 20 is a flow chart showing a second example of
introduction and allocation of an extension band.

FIG. 21 is a flow chart showing a third example of
introduction and allocation of an extension band.
FIG. 22 is a view showing an example of the dynamic
change of the extension band for easy understanding.
FIG. 23 is a flow chart showing an example of
changing both the main band and the extension band.
FIG. 24 is a flow chart showing an example of the
dynamic change of both the main band and the extension
band for easy understanding.
FIG. 25 is a view showing an example of the hardware
configuration on the return side of response (CQI)
information to a pilot signal.
FIG. 26 is a view showing a table for explaining
high efficiency transmission of the used frequency band
information.
FIG. 27 is a view showing an example of the dynamic
change of the extension band.
FIG. 28 is a view showing a first example of a band
extension pattern.
FIG. 29 is a view showing a second example of a band
extension pattern.
FIG. 30 is a view showing a third example of a band
extension pattern.
FIG. 31 is a view showing an example of the hardware
configuration of a communications apparatus (transmission
side) according to Embodiment 10.
FIG. 32 is a flow chart showing an example of the
operation in the apparatus of FIG. 31.
FIG. 33 is a view for explaining Embodiment 11.
FIG. 34 is a view showing the gist of the prior art
disclosed in Patent Document 1.
FIG. 35 is a view showing the gist of the prior art
disclosed in Patent Document 2.
FIG. 36 is a view showing the gist of the prior art
disclosed in Patent Document 3.
FIG. 37 is a view showing the gist of the prior art
disclosed in Patent Document 4.

BEST MODE FOR CARRYING OUT THE INVENTION
First of all, to speed the understanding of the
present invention, the prior arts (Patent Documents 1 to
4) explained above will be explained with reference to
the drawings.
FIG. 34 is a view showing the gist of the prior
art disclosed in Patent Document 1. The figure shows the
allocation of frequencies to for example seven users U1
to U7 (top part). The bottom parts shows details of the
allocation of a series of subcarrier to the users Ul and
U2. The abscissa is the frequency.
The present system is characterized by
consecutively arranging a plurality of carriers for the
frequency bands allocated at the transmission side,
dividing them into a plurality of subcarriers in
accordance with the users (Ul to U7), and consecutively
arranging these.
Specifically, for example, the overall
frequency band able to be used in one communications
system is set as 20 MHz, and 250 subcarriers are set
there. Accordingly, the bandwidth of each subcarrier
becomes 20 MHz/250 = 80 kHz. Then, these 250 subcarriers
are used while being dynamically allocated among the
plurality of users (U1 to U7).
At this time, for example, the subcarriers are
dynamically allocated, for example, 50 subcarriers are
allocated to a user A (U2) and 75 subcarriers are
allocated to another user B (Ul), to make the number of
subcarriers used variable.
Along with that, the used frequency band
becomes 50 x 80 kHz = 4 MHz for the user A and becomes 75
x 80 kHz = 6 MHz for the user B. That is, the used
frequency band is made variable for each user. In this
case, it is assumed that the allocated subcarriers are
consecutive on the frequency axis. Note that it is also
possible to further make the sizes of the divisions of
the frequency band variable.

FIG. 35 is a view showing the gist of the prior
art disclosed in Patent Document 2. The figure is a view
showing the state of allocation of the common control
channel and the data channel on the frequency axis.
In the present system, in a multicarrier CDMA
system, the subcarriers dedicated to the transmission of
the control signal and the subcarriers dedicated to the
transmission of data (data channel) are separately set.
The common control channel thereof is spread by a unique
spread code. Accordingly, when this common control
channel is received, it is sufficient to demodulate
specific subcarriers, so the amount of signal processing
thereof can be reduced.
FIG. 36 is a view showing the gist of the prior
art disclosed in Patent Document 3. The figure shows
making the frequency band of the data channel in FIG. 35
described above variable in accordance with a propagation
distance (communication distance with the base station).
Note that the transmission power is changed (large -
medium - small).
The present system is a system for realizing
variable speed communication by making the transmission
rate per subcarrier fixed and making the number of
subcarriers allocated to the user variable. When the
distance between the base station and the terminal is
short, the transmission power of each subcarrier is made
small and many subcarriers are allocated, while when that
distance is long, the transmission power of each
subcarrier is made large and a small number of
subcarriers are allocated.
Further, the number of subcarriers used for the
common control channel is made small, while a large
number of subcarriers are allocated with respect to the
data communications use channel (data channel). The two
are completely separately arranged along the frequency
axis. Note that the subcarriers dedicated to the common
control channel are used to notify the center subcarrier

number of the subcarriers allocated for the data channel
and the number of used subcarriers from the base station
to the mobile station.
FIG. 37 is a view showing the gist of the prior
art disclosed in Patent Document 4. The figure shows that
the bandwidth of each subcarrier is made variable in
accordance with whether or not the propagation
environment is good.
The present system changes the bandwidth of
each subcarrier while making a total number of
subcarriers constant in accordance with the condition of
the propagation environment in wireless transmission. For
example, when the propagation condition becomes poor, the
band of each subcarrier is made wider. Due to this, the
transmission can be carried out without changing the
total subcarriers, therefore the transmission rate can be
maintained constant without regard to the propagation
environment.
The present invention solves the already
explained problems of the prior arts (Patent Documents 1
to 4) explained with reference to FIG. 34 to FIG. 37
explained above. This will be explained in detail below
with reference to the drawings.
FIG. 1 is a view showing the basic
configuration of a communications apparatus (transmission
side) according to the present invention, and
FIG. 2 is a view showing the basic configuration of
a communications apparatus (reception side) according to
the present invention.
In FIG. 1, reference numeral 10 indicates the
communications apparatus (transmission side), and in FIG.
2, reference numeral 20 indicates the communications
apparatus (reception side). These are accommodated in the
same communications system (mobile communications
system). Note that as already explained, the
communications apparatus 10 may be a base station and the
communications apparatus 20 may be a terminal, or vice

versa. The present invention can be applied to both
cases, but for easier understanding, in the following
explanation, the communications apparatus 10 on the
transmission side will be assumed as the base station,
and the communications apparatus 20 on the reception side
will be assumed as a terminal unless otherwise indicated.
First, referring to FIG. 1, the selection
function in particular of a used frequency band
selecting/setting unit 15 is used to select the used
frequency band to be used with the other communications
apparatus 20. The "used frequency band information" If
(frequency) according to this selection is input to a
transmission data generation unit 11 where transmission
data Dt (transmission) combined integrally with
transmission data (user data) Du (user) to be transmitted
to the communications apparatus 20 is generated.
Accordingly, the transmission data Dt includes the
transmission data Du and the used frequency band
information If, but in actuality further includes also
other "communication control information" let (control).
This information let is the information concerning a used
modulation scheme for example QAM and information etc.
concerning a one time transmission data amount of the
transmission data Du.
The above transmission data Dt is modulated in
a predetermined way at a modulation unit 12, then input
to the next multicarrier transmission sender unit 13.
This sender unit 13 is supplied with a band set
instruction signal Sb (band) instructing processing for
transmission at the above selected used frequency band by
the setting function of the above used frequency band
selecting/setting unit 15. The sender unit 13 performs
the processing for signal transmission by multicarrier
transmission at the frequency band based on this signal
Sb.
Further, a wireless unit 14 converts the
frequency conversion of the transmission data signal St

from the above sender unit 13 and transmits this from the
next antenna AT toward another communications apparatus
(terminal) 20.
On the other hand, referring to FIG. 2, the
wireless signal from the above antenna AT (FIG. 1) is
received at the antenna AT (FIG. 2) and further converted
in frequency by a wireless unit 21 to be a received data
signal Sr which is then input to a multicarrier
transmission receiver unit 22. This receiver unit 22
processes the received data signal Sr for signal
reception according to the multicarrier transmission,
then the next demodulation unit 23 demodulates the signal
after the signal reception processing.
The demodulated received data Dr is decoded at
a received data decoding unit 24 and separated to the
original transmission data Du and the previously set used
frequency band information If explained before. Further,
the above communication control information let is also
separated from that data Dr. Note that the units to be
controlled according to this information let are not
directly related to the gist of the present invention, so
explanations are omitted.
As explained above, the original used frequency
band information If obtained by separation from the
received data Dr is input to a used frequency band
setting unit 25. The setting unit 25 receives this
information If and reproduces the above band set
instruction signal Sb. This signal Sb is supplied to the
above multicarrier transmission receiver unit 22, then
this receiver unit 22 performs processing for signal
reception according to the multicarrier transmission by
using the frequency band selected on the transmission
side. Note that the previously determined frequency band
may be selected in the initial stage of establishment of
the wireless channel.
In the present invention, the transmission side
(10) and the reception side (20) can use the same used

frequency band by the above-explained band set
instruction signal Sb. Further, based on that signal Sb,
that used frequency band can be simultaneously extended,
reduced, or changed at both of the transmission side (10)
and the reception side (20). Thus, the object of the
present invention explained before can be achieved.
The basic configuration of the present
invention explained above will be explained a little more
concretely in comparison with the above prior arts.
In the present invention, the frequency band
usable in the communications system as a whole is divided
into a plurality of bands. For example, when the used
frequency band of the communications system as a whole is
set as 20 MHz, it is divided into four bands of 5 MHz
each. One band 5 MHz is used to transmit the information
of the control channel for transmitting the used
frequency band information and the transmission channel
(data channel) for transmitting the transmission data.
According to the present invention, as
explained before, the frequency band for transmitting at
least the control channel is defined as the "main band"
and a further extended frequency band is defined as an
"extension band". For example, when considering this in
an OFDM communications system, 100 subcarriers are
included in one band 5 MHz, the bandwidth of each
subcarrier is 50 kHz, and the information of the control
channel and the data channel are transmitted by using the
series of these 100 subcarriers. The two information may
be multiplexed by time division multiplexing, frequency
division multiplexing, or code division multiplexing.
As explained above, unlike Patent Document 3
(Japanese Patent Publication (A) No. 2004-214746), the
information of the "main band" is received and decoded to
learn the used frequency band (or number of used
frequency bands), therefore, the used frequency band can
be easily extended, reduced, and changed. Further, due to
this, unlike Patent Document 1 (Japanese Patent

Publication (A) No. 9-205411) and Patent Document 3
(Japanese Patent Publication No. 2004-214746), the
configuration of the reception unit is simplified.
Further, if making the number of subcarriers
per frequency band constant, the number of subcarriers
will change with a ratio of a whole number along with a
change of the number of used frequency bands.
Accordingly, when compared with Patent Document 3
(Japanese Patent Publication (A) No. 2004-214746) in
which the subcarriers dynamically change, the
configuration of the reception unit is simplified.
Further, by designating the used frequency band
from the base station to the terminals in advance, the
extension band described above can be easily changed and
added to and even the main band can be changed.
Further, if making the bandwidth of each
subcarrier fixed as explained above, the used frequency
band can be changed without influencing other users as in
Patent Document 4 (Japanese Patent Publication (A) No.
2002-330467). Various embodiments according to the
present invention will be explained below.
[Embodiment 1: Setting of used frequency band]
First, describing some characteristic features
disclosed in the present Embodiment 1, these are as
follows. The principal points of these characteristic
features are as already described and reside in the
following three points (i) to (iii):
(i) A specific frequency band from among a
plurality of frequency bands formed by dividing the
overall frequency band allocated to a communications
system is set, and that specific frequency band is used
to transmit "used frequency band information" If
determining which remaining frequency band is to be used
between communications apparatuses (10, 20), (ii) that
specific frequency band is set as a "main band" in the
overall frequency band, and that main band transmits, in
addition to the used frequency band information If, data

information Du, and (iii) among the above-explained
plurality of frequency bands, at least one frequency band
set from among the frequency bands other than above "main
band" is defined as an "extension band", and that
extension band mainly transmits further data information
(Du) .
Next, some principal points further disclosed
in the present Embodiment 1 reside in the following four
points (iv) to (vii):
(iv) The above "main band" is set fixedly at
the time of the establishment of the wireless channel
between the communications apparatuses (10, 20),
(v) when there are a plurality of communications
apparatuses (20), "main bands" are individually set for
the above plurality of frequency bands and, at the same
time, main bands are individually assigned corresponding
to these plurality of communications apparatuses (20),
(vi) two or more communications apparatuses (20) can
simultaneously use the same "main band" by time division
multiplexing and/or code division multiplexing, and
(vii) further, the number of extension bands is
changed in accordance with the predetermined transmission
rate of the data information (Du).
FIG. 3 is a view showing a concrete example of
the communications apparatus (transmission side) 10
according to the present invention, and
FIG. 4 is a view showing a concrete example of the
communications apparatus (reception side) 20 according to
the present invention. Note that, same components will be
indicated by same reference numerals or symbols
throughout all of the figures. Further, the concrete
examples shown in FIG. 3 and FIG. 4 are not only applied
to the present Embodiment 1, but also commonly applied to
the other Embodiments 2 to 10 explained later.
Referring to the communications apparatus
(transmission side) 10 first, the parts corresponding to
the components 11 to 15 and Du, Dt, St, and Sb shown in

FIG. 1 are shown assigned these reference numerals or
symbols 11 to 15 and Du, Dt, St, and Sb.
The transmission data generation unit 11 is
configured by a data block preparation unit 31, an
encoding unit 32, a transmission data amount calculation
unit 33, an encoding unit 34, and a multiplexing unit
(Mux) 35 according to the example of the present figure.
Based on the used frequency band information If
from the above used frequency band selecting/setting unit
15, the transmission data amount calculation unit 33
first calculates a transmission data length, then the
data block preparation unit 31 prepares data blocks for
each transmission data length. Further, the encoding unit
32 encodes the transmission data by using that
transmission data length.
The above used frequency band information If is
encoded together with the communications control
information let indicating the used modulation scheme
etc. at the encoding unit 34. Note that the encoding
units 32 and 34 may encode Du and If all together as one
encoding unit.
The encoded outputs from the two encoding units
32 and 34 are multiplexed at the multiplexing unit (Mux)
35 and become the already explained transmission data Dt.
This data Dt is further modulated at the modulation unit
12 as explained before. As the method of this
multiplexing, there are frequency division multiplexing
separating subcarriers and using the same, time division
multiplexing (by using for example a frame format shown
in FIG. 16), code division multiplexing etc. Further, as
the modulation scheme by the modulation unit 12, there
are QPSK, 16QAM, 64QAM, etc.
E-0060] - Next, when looking at the multicarrier
transmission sender unit 13, in the example shown in the
present figure, this is configured by components 36, 37,
38, 39, and 40. Note that this is shown as an example
based on communications according to OFDM. Another

example based on communications according to MC-CDMA is
shown in FIG. 7 (FIG. 8).
The demultiplexing unit (DeMux) 36
demultiplexes this into the information belonging to the
"main band" and the information belonging to the
"extension bands". The information belonging to the "main
band" is converted to a parallel signal at a
serial/parallel converter (S/P) 37, then a time-frequency
transform is applied to the parallel signal at an Inverse
Fast Fourier Transform unit (IFFT) 38. The parallel
signal transformed into frequency is converted to a
serial signal again at a parallel/serial converter (P/S)
39. Further, a guard interval (GI) insertion unit 40
inserts a guard interval GI into the serial signal for
preventing inter-symbol interference.
The thus obtained transmission data signal St
is input to the wireless unit 14. This wireless unit 14
is, according to the example of the present figure,
configured by a general mixer 41, a local oscillator 42,
and a power amplifier 44 (a D/A converter, a filter, etc.
are omitted) and transmits the transmission data signal
St from the antenna At. In this case, an adder unit 43 is
provided in the middle.
The adder unit 43 applies the same processing
as the processing for the "main band" by the above-
explained components 37, 38, 39, 40, 41, and 42 with
respect to the information belonging to the above
"extension bands" demultiplexed at the demultiplexing
unit (DeMux) 36 as explained before by the components
37', 38', 39', 40', 41', and 42', obtains the
transmission data signal St on the "extension band" side,
and combines the same together with the already explained
transmission data signal St on the "main band" side.
f side described above is generated only when data
transmission by the "extension bands" is needed. Whether
or not it is needed is determined according to the band

set instruction signal Sb from the already explained
selecting/setting unit 15.
Referring to FIG. 4 next, parts corresponding
to the components 21 to 25 and Sr, Dr, Du, If, and Sb
shown in FIG. 2 are shown assigned the reference numerals
21 to 25 and symbols Sr, Dr, Du, If, and Sb.
The wireless unit 21, according to the example
of the present figure, eliminates an undesired band of a
signal in the signal received from the antenna AT by a
band pass filter (BPF) 51, converts the remainder to a
predetermined reception frequency by the mixer 52 and the
local oscillator 53, and thereby obtains the received
data signal Sr.
This received data signal Sr is input to the
multicarrier transmission receiver unit 22 and processed.
This receiver unit 22 is, according to the example of the
present figure, configured by the components 54, 55, 56,
57, and 58.
First, the guard interval (GI) elimination unit
54 eliminates the guard interval inserted at the
transmission side. The signal after the GI elimination is
further converted to a parallel signal at the
serial/parallel converter (S/P) 55. The Fast Fourier
Transform unit (FFT) 56 applies a frequency-time
transform to the parallel signal. The time transformed
parallel signal is converted to a serial signal again at
the parallel/serial converter (P/S) 57.
On the other hand, when the signal received
from the antenna AT contains information belonging to an
"extension band", the mixer 52' and the local oscillator
53' extract the signal of the "extension band" and apply
the same processing as the processing by the above-
explained components 55 to 57 by the same components S/P
55', FFT 56', and P/S 57' to obtain a time-transformed
serial signal.
The serial signals from the above
parallel/serial converters 57 and 57' are multiplexed at

the multiplexing unit (Mux) 58 and further demodulated at
the demodulation unit 23. Note that when only information
belonging to the "main band" is transmitted, the above
multiplexing unit 58 does not perform the multiplexing,
but only passes the signal therethrough.
The signal from the multiplexing unit 58
becomes the received data Dr demodulated at the next
demodulation unit 23, then is input to the received data
decoding unit 24. This decoding unit 24 is, according to
the example of the present figure, configured by a
demultiplexing unit (DeMux) 59, a data channel decoding
unit 60, a control channel decoding unit 61, and a
transmission data amount calculation unit 62.
The above demultiplexing unit 24 demultiplexes
the received data Dr to data channel side data and
control channel side data and distributes these to the
decoding unit 60 and the decoding unit 61. From the
decoding unit 60, the original transmission data Du is
reproduced based on the transmission data amount
explained later. On the other hand, from the decoding
unit 61, the "used frequency band information" If is
reproduced.
The above information If from the decoding unit
61 is input to the transmission data amount calculation
unit 62 on the one hand, the data length of the received
transmission data is calculated here based on that If,
and the transmission data is decoded by the above
decoding unit 60 based on this data length.
The above information If from the decoding unit
61 is given to the already explained used frequency band
setting unit 25 on the other hand, where the above band
set instruction signal Sb is generated. Then, according
to the content of this signal Sb, the circuit portions
(22, 58, 59) are set corresponding to the selected
frequency band by the shown dotted line route. Note that
the received data decoding unit 24 of FIG. 4 may be
configured so that the received data Dr is input to one

decoding unit (making the decoding units 60 and 61
common) at first and decoded, then demultiplexed to the
data channel and the control channel at the
demultiplexing unit 59.
In the configuration of FIG. 3 and FIG. 4
explained above, the frequency band of the "main band" is
fixed, and only the frequency bands of the "extension
bands" are variable. However, in a certain embodiment of
the present invention, not only the "extension bands",
but also the "main band" can be made variable in
frequency bands. An example of a configuration
accomplishing this is shown in the drawings.
FIG. 5 is a view showing a modification of the
communications apparatus (transmission side) 10 according
to the present invention, and FIG. 6 is a view showing a
modification of a communications control device
(reception side) 20 according to the present invention.
The difference between the configuration shown
in these FIG. 5 and FIG. 6 and the configuration shown in
FIG. 3 and FIG. 4 explained before resides in that, in
FIG. 5, the scope of instruction by the band set
instruction signal Sb from the used frequency band
selecting/setting unit 15 reaches not only the "extension
band" side (37' to 42') (case of FIG. 3), but also the
"main band" side (37 to 42). Further, the difference
resides in that, in FIG. 6, the scope of instruction by
the band set instruction signal Sb from the used
frequency band setting unit 25 reaches not only the
"extension band" side (52' to 57') (case of FIG. 4), but
also the "main band" side (52 to 57). Thus, the change of
the frequency band of the "main band" also becomes
possible.
Further, the explanation of the concrete
example explained above was predicated on communications
by OFDM, but other than this, it is also possible to
explain it based on communications according to the MC-
CDMA. Also, an example of the communications apparatus in

this latter case (MC-CDMA base) is shown here.
FIG. 7 is a view showing another modification
of the communications apparatus (transmission side) 10
according to the present invention, and FIG. 8 is a view
showing another modification of the communications
apparatus (reception side) 20 according to the present
invention.
For example, when comparing the above FIG. 5
and FIG. 6 and the present FIG. 7 and FIG. 8, on the
transmission side (10), the configuration of the
multicarrier transmission sender unit 13 is different,
and on the reception side (20), the configuration of the
multicarrier transmission receiver unit 22 is different.
Namely, in the sender unit 13 shown in FIG. 7,
the difference resides in the point that a copier unit 46
and a multiplication unit 47 are used. Further, in the
receiver unit 22 shown in FIG. 8, the difference resides
in the point that a multiplication unit 65 and a
combining unit (£) 66 are used.
First, the transmission operation will be
explained by using FIG. 7. The generated transmission
data is modulated and copied by the number of subcarriers
at the copier unit 46. The multiplication unit 47
multiplies the copied signals by spread codes (C1, C2 '"
Cn). The IFFT units (38, 38') apply IFFT to the results
to apply a time-frequency transform. Then, the GI
insertion unit 40 inserts a GI, then the signal is
converted in frequency and transmitted from the antenna
AT. Further, the setting of the multicarrier transmission
sender 13 is changed based on the used frequency band
selected at the used frequency band selection unit 15.
Next, a reception operation will be explained
by using FIG. 8. First, the received signal is frequency
converted to obtain a base band signal, then the GI is
eliminated at the GI elimination unit 54. Next, the
signal is converted from a serial to parallel format (55,
55'), and each of the parallel signals is multiplied by

the spread codes (C1, C2 .... Cn) at the multiplication unit
65 and despread. The results thereof are subjected to FFT
at the FFT units (56, 56'), a frequency-time transform is
carried out, then the results are summed up at the
combining unit 66. The result of this is demodulated at
the demodulation unit 23. Below, the same processing as
that explained before is carried out to extract the used
frequency band information If. Then, based on the
extracted used frequency band information If, the setting
of the multicarrier transmission receiver unit 22 is
changed. Note that, in FIG. 7 and FIG. 8, when the used
frequency band is changed, the number n of codes the
frequency spread may be made variable. When MC-CDMA is
used as described above, the hardware configuration can
be simplified in comparison with the OFDM. Further, on
the other hand, there arises a necessity of making the
number of point of FFT and IFFT dynamically variable, so
the control becomes complex.
Below, the present Embodiment 1 will be further
explained with reference to the arrangement of the
frequency bands.
f©0£5i- A communications system able to change the used
frequency band using OFDM etc. transmits the used
frequency band information If by using a specific
frequency band. Then, by demodulating and decoding the
specific frequency band, the used frequency band If can
be obtained. By this information If, the communications
in an extension band become possible. This is based on
division of the overall frequency band as follows in the
present invention.
£0086]. FIG. 9 is a view showing the pattern of
frequency division in a communications system. The series
of subcarriers of the present figure show the overall
frequency band assigned to the communications system.
This overall frequency band is divided into a plurality
of frequency bands. In the present figure, the example of
division into four is shown, that is, the band is divided

into four frequency bands, that is, "BAND 1", "BAND 2",
"BAND 3", and "BAND 4". Then, any of these "BAND 1" to
"BAND 4" is selected and defined as the above "main
band", while another band is selected and defined as an
above "extension band".
FIG. 10 is a view showing the state of
selecting one "main band" and one "extension band". For
example the above band 1 is selected as the "main band",
and for example the above band 2 is selected as an
"extension band". As explained before, the "main band" is
assigned to the transmission of the control channel (CH)
and the data channel (CH), and the "extension band" is
assigned to the further transmission of the data channel.
The main band used by a certain terminal is determined by
for example the base station or the higher base station
controller. Alternatively, converse to this, the main
band may be designated from the terminal side to the base
station side.
The above main band may be fixed in advance in
the communications system or may be set at the time of
establishment of a wireless channel between
communications apparatuses (base station and terminal).
The setting may be fixed until the communication is
completed.
Further, when there are a plurality of
communications apparatuses (user terminals), a different
main band may be set for each user terminal. This
situation will be shown in the figure.
FIG. 11 is a view showing a first example of a
mode of assignment of main bands for a plurality of
users, and FIG. 12 is a view showing a second example of
a mode of assignment of main bands for a plurality of
users. Note that these modes can also be applied to
extension bands.
Referring to FIG. 11 first, main bands of users
U1 to U4 are individually assigned to a plurality of
frequency bands, that is, band 1 to band 4. Note that, in

this case, the number of users is restricted by the
number of bands.
Therefore, as shown in FIG. 12, the same main
band is simultaneously assigned with respect to a
plurality of communications apparatuses (user terminals).
This becomes possible by user multiplexing. As this
multiplexing method, there are time division multiplexing
and code division multiplexing or multiplexing combining
these.
Further, in the present Embodiment 1, also the
number of used frequency bands (band 1 to band 4) can be
changed in accordance with the predetermined transmission
rate of the data information (transmission data Du).
Namely, the base station considers the
communication situation, propagation environment, used
frequency band, etc. of other terminals in the middle of
communications. When judging that another frequency band
can be used, it extends the used frequency band. Note
that at the time of extension, the available frequency
can be extended on a priority basis according to the
degree of priority of communications between the
terminals, the predetermined transmission rate, and other
transmission data attributes (QoS: Quality of Service).
In this way, since the used frequency band
information If is transmitted by using a specific
frequency band (main band), the reception side need only
receive that main band first and does not have to receive
and demodulate and decode up to the other frequency
bands. Further, by using the extension band, a further
speed-up of the transmission rate becomes possible, and
an improvement of the frequency utilization efficiency
can be achieved.
[Embodiment 2: Dynamic change of main band]
First, describing some characteristic features
disclosed in the present Embodiment 2, they are as
follows:
i) The frequency band occupied as the main band

among the plurality of frequency bands (band 1 to band 4)
is made variable along with the elapse of time,
ii) whether or not the propagation environment
between communications apparatuses (10, 20) is good is
judged, then the frequency band of the best propagation
environment among the above plurality of frequency bands
or the frequency band next to this is selected and set as
the main band,
iii) at the time of new setting of the main band,
the change of the frequency band is notified to the
communications apparatus of the other party in advance,
iv) the result of detection of the transmission
quality (CQI) obtained in response to a pilot channel or
pilot signal transmitted between communications
apparatuses is used to judge whether or not the above-
explained propagation environment is good,
v) the judgment of whether or not the propagation
environment is good is performed for all of the above
plurality of frequency bands sequentially or
simultaneously; and
vi) further, the result of judgment of the quality
of the propagation environment is sent to the
communications apparatus of the other party by using the
control channel of a specific frequency band.
In general, the transmission characteristic of
the control channel must be better in terms of the
transmission quality in comparison with the data channel.
First, this is because the channel through which the data
is to be transmitted must be reliably set. Namely, the
main band including the control channel must select the
frequency band having a better propagation environment so
that the transmission quality thereof becomes good in
comparison with the extension band. Therefore, a concrete
example of free selection of the frequency band set as
the main band in accordance with quality of the
propagation environment will be explained.
FIG. 13 is a flow chart showing an example of

dynamically changing the frequency band of a main band.
Note that the basic transmission/reception operation
between the base station and a terminal is as explained
in the above Embodiment 1. Further, in FIG. 13, each
solid line block represents an operation of the base
station, and each dotted line block represents an
operation of the terminal. Note that the reverse may also
apply (true for other flow charts explained later as
well).
Step S11: Send pilot channel signal at each
frequency band.
Step S12: Receive all pilot channel signals,
Step S13: Calculate each SNR etc. and convert it to
CQI, and
Step S14: Transmit each CQI by uplink control
channel.
Step S15: Receive each CQU,
Step S16: Select used frequency band and determine
timing of change of band, and
Step S17: Transmit the selected used frequency band
and determined change timing by downlink control channel.
Step S18: Receive the above used frequency band
and change timing,
Step S19: Change setting for each circuit unit at
the above change timing, and
Step S20: Start reception operation by using main
band after that change.
Note that the above SNR indicates the signal to
noise ratio, and CQI a channel quality indicator. Note
that a definition indicating CQI is described in TS25.212
Release 5 etc. of 3GPP (3rd Generation Partnership
Project http://www.3gpp.org/). The specifications are
recorded at http://www.3gpp.org/ftp/Specs/html-info/25-
series.htm.
The processing for making the main band
variable along with the elapse of time according to the
above flow chart showing one example in FIG. 13 can be

accomplished by for example the following hardware
configuration.
FIGS. 14A and 14B are views showing an example
of the hardware configuration of the transmission side of
the pilot signal, and FIGS. 15A and 15B are views showing
an example of the hardware configuration of the return
side of the response (CQI) information to the pilot
signal.
The configurations shown in FIGS. 14A and 14B
are substantially the same as the configuration of FIG. 3
(or FIG. 5) explained before. The elements to be newly
noted are a pilot signal Sp (or pilot channel) on the
left end of FIG. 14A, and a multiplexing unit (Mux) 71
for multiplexing the pilot signal Sp and the used
frequency band information If and a CQI extraction unit
72 in FIG. 14B. The configuration of this FIG. 14B is
substantially the same as the configuration of FIG. 4 (or
FIG. 6) explained before. The component to be newly noted
is a CQI extraction unit 72 on the lower side of the
center of the present figure. Note that, in FIG. 14B,
units corresponding to those in FIG. 4 are given the
reference numerals 52, 53, 54, '" used in FIG. 4 plus 100
and thereby indicated as 152, 153, 154, '".
Further, the configurations shown in FIG. 15A
and 15B are the same as the configuration of FIG. 4 (or
FIG. 6) explained before. The components to be newly
noted are an SNR measurement unit 7 5 and a CQI
calculation unit 76 in FIG. 15A and further an encoding
unit 78 and an adder unit 79 in FIG. 15B after passing
through a loop back path 77. Note that in FIG. 15A, parts
corresponding to those in FIG. 4 (reception side) are
indicated by using the reference numerals 52, 53, 54, ....
used in FIG. 4, while in FIG. 15B, parts corresponding to
those in FIG. 3 (transmission side) are given the
reference numerals 12, 37, 38, ... used in FIG. 3 plus 100
and thereby indicated as 112, 137, 138, ....

The above pilot signal Sp is transmitted after
multiplexing with other transmission information in
actual operations. This multiplexing method includes for
example the following two schemes:
FIG. 16 is a view showing an example of first
multiplexing of a pilot signal, and FIG. 17 is a view
showing an example of second multiplexing of a pilot
signal. Note that, in both figures, "P" represents the
pilot signal Sp, "C" represents the already explained
communication control information Ict, and "D" represents
the already explained transmission data Du.
FIG. 16 shows that the pilot signal Sp is
multiplexed along with the elapsed time, while FIG. 17
shows that the pilot signal Sp is multiplexed along with
both the elapsed time and the frequency.
FIG. 18 is a view showing an example of the
dynamic change of the main band in the above-explained
Embodiment 2 for easier understanding. Time elapses from
the top toward the bottom in the present figure. Along
with the elapse of time, the main band changes as for
example "BAND 1" → "BAND 2" → "BAND 3" → "BAND 4"
following the better propagation environment.
Thus, the base station multiplexes the signal
for measuring the propagation environment (pilot) in all
of the frequency bands used and transmits this as the
control channel. Note that, in actual use, a case not
including the transmission data Du is also assumed.
Further, the pilot channel may be provided in place of
the pilot signal Sp.
The terminal receives the pilot channel signals
for all frequency bands (band 1 to band 4), measures the
reception conditions and propagation environments, for
example the SNR and CIR (carrier to interference ratio),
calculates the above CQIs from the measurement values,
and sequentially or simultaneously transmits the same to
the base station for each band by using the uplink
control channel. Note that it may also transmit the

measurement results of the above CIR and SNR as they are.
The base station receives the uplink control
channel signal and demodulates and decodes the CQIs. It
selects the frequency band having the best CQI value from
among the plurality of CQIs as the main band. It sends
this selection result and the timing of change of the
main band on the downlink control channel to the
terminal.
The terminal receives this downlink control
channel signal and demodulates and decodes this to
extract the information of the used frequency band and
timing of change. Then, at the timing of change, it
changes the used frequency band. Note that the timing of
change may be determined according to for example an
absolute time or relative time or a slot unit. Further,
it is also possible not to transmit the timing of change,
but set it as after, e.g., 5 slots from the transmission
of the downlink control channel signal etc. and thereby
fix it for the system.
In the above description, the frequency band
having the best propagation environment was selected as
the main band, but a case where the best frequency band
cannot be selected due to the situation of the other
terminal may also be considered. In such case, the second
best frequency band next to that may be selected.
Note that here the main band was selected by
the base station, but the terminal may similarly select
the frequency band having the best propagation
environment and transmit this to the base station.
The SNRs, CIRs, etc. may be measured in the
terminal simultaneously for all frequency bands as
explained above or in a time division manner. Further, in
a situation where bands having narrow frequency band
widths continue, the propagation environment will not
largely vary, therefore, in such case, only one frequency
band need be measured. Further, the measurement value
thereof may be made a mean value after measurement over a

certain time.
[0119] Further, in Embodiment 1, the extension band
was explained by assuming transmission of only the
transmission data Du, but to measure the propagation
environment of each frequency band, in addition to the
transmission data Du, a pilot channel or pilot signal may
also be transmitted.
[0120] The above explanation was given with reference
to transmission from the base station to a terminal, but
the present invention can similarly be conversely applied
to transmission from a terminal to the base station.
[0121] As already explained, in general, the
transmission characteristic of the control channel must
be better than the transmission characteristic of the
data channel in transmission quality. Accordingly, for
the main band including the control channel, it is
necessary to select a frequency band having a good
propagation environment. According to the above-explained
operation, it becomes possible to select a frequency band
under the best propagation environment as the main band.
Further, even when the propagation environment changes
along with the elapse of time, it becomes possible to
always select the frequency band under the best
propagation environment as the main band.
[0122] Due to this, not only the transmission error of
the control channel information is reduced, but also the
hardware settings of the reception side become easy, and
improvement of the transmission quality becomes possible.
Further, it is also possible to reduce the number of
times of data retransmission due to transmission error,
therefore the transmission rate can be further increased.
[0123] Further, the main band is variably set,
therefore unbalance of the utilization situation (load)
among frequency bands can be avoided and improvement of
the frequency utilization efficiency can be achieved.
[Embodiment 3: Dynamic change of extension band]
Describing some characteristic features disclosed in

the present Embodiment 3 first, they are as follows:
i) The frequency band set as an extension band
among a plurality of frequency bands (band 1 to band 4)
is made variable along with the elapse of time,
ii) whether or not the propagation environment
between communications apparatuses (10, 20) is good is
judged, and the frequency band next to the frequency band
having the best propagation environment among the above
plurality of frequency bands is selected and set as the
extension band.
iii) Further, the frequency band usable by the
communications apparatuses (10, 20) is restricted at the
time of establishment of the wireless channel, and the
main band and the extension band are dynamically assigned
within that restricted frequency band.
iv) Furthermore, the setting information of the
frequency band to be set as the extension band is
notified to the communications apparatus of the other
party in advance for the extension,
v) frequency band setting information concerning the
frequency band for which extension is possible or change
is possible is received from the communications apparatus
of the other party, and the extension band or main band
is changed by this, and
vi) further, change timing information concerning
the timing of the change is received.
vii) Further, the result of judgment as to
whether or not the propagation environment is good is
transmitted to the communications apparatus of the other
party by using a control channel of a specific frequency
band,
viii) whether or not the propagation environment is
good is judged using the result of detection of the
transmission quality (CQI) returned in response to pilot
channels or pilot signals transmitted between the
communications apparatuses (10, 20),
ix) based on at least one of the available frequency

band of the related communications apparatus, the quality
of the propagation environment at each frequency band,
the usage situation of each frequency band, and the
predetermined transmission rate of the data information
(Du), the necessity of the setting or change of the
extension band is judged, and
x) at the time of new setting of the above extension
band, the change of the frequency band is notified to the
communications apparatus of the other party in advance.
FIG. 19 is a flow chart showing a first example
of the introduction and change of an extension band,
FIG. 20 is a flow chart showing a second example of
the introduction and change of an extension band, and
FIG. 21 is a flow chart showing a third example of
the introduction and change of an extension band.
Specifically, FIG. 19 shows a control flow in a
case of selecting an extension band by using the used
frequency band of the terminal and the CQI of each
frequency band. Further, FIG. 20 shows a control flow in
a case of selecting an extension band by using the used
frequency band thereof, the usage situation of each
frequency band, and the predetermined transmission rate
of the transmission data. Further, FIG. 21 shows a
control flow in a case of selecting an extension band by
using the used frequency band of the terminal, the CQI of
each frequency band, the usage situation of each
frequency band, and the predetermined transmission rate
of the transmission data.
In FIG. 19,
Step S21: Transmit available frequency band.
Step S22: Receive available frequency band, and
Step S23: transmit pilot channel signals by using
available frequency band.
Step S24: Receive all pilot channel signals,
calculate SNRs etc., and convert it to CQIs, and
Step S25: transmit CQIs through uplink control
channel.

Step S26: Receive above CQIs,
Step S27: select existence of need of extension from
CQIs, select extended frequency band, and determine
timing of change thereof, and
Step S28: transmit extended frequency band and
timing of change through downlink control channel.
Step S29: Receive above extended frequency band
and timing of change,
Step S30: change setting for each circuit part at
the timing of change, and
Step S31: start reception operation by using
extension band after that change.
Next, in FIG. 20,
Step S41: transmit available frequency band.
Step S42: Receive above available frequency
band,
Step S43: confirm usage situations of frequency
bands and predetermined transmission rate of transmission
data Du,
Step S44: select existence of necessity for
extension, select extended frequency band, and determine
timing of change thereof, and
Step S45: transmit extended frequency band and
timing of change through downlink control channel.
Step S4 6: Receive above extended frequency band
and timing of change,
Step S47: change setting for each circuit unit at
the timing of change, and
Step S48: start reception operation by using
extension band after that change.
Further, in FIG. 21,
Step S51: transmit available frequency band.
Step S52: Receive available frequency band, and
Step S53: transmit pilot channel signals by using
available frequency band.
Step S54: Receive all pilot channel signals,
then calculate SNRs etc., convert to CQIs, and

Step S55: transmit above CQIs through uplink control
channel.
Step S56: Receive above CQIs,
Step S57: confirm usage situations of frequency
bands and predetermined transmission rate of transmission
data Du,
Step S58: select existence of necessity for
extension, select extended frequency band, and determine
timing of change thereof, and
Step S45: transmit extended frequency band and
timing of change through downlink control channel.
Step S60: Receive above extended frequency band
and timing of change,
Step S61: change setting for each circuit unit at
the timing of change, and
Step S62: start reception operation by using
extension band after that change.
In the present Embodiment 3, dynamic change of
the extension band is explained. In general, at the time
of the setting of a channel (time of establishment of
wireless channel), the frequency band available by a
terminal is transmitted from the terminal to the base
station (or base station controller). This is the above-
explained terminal available frequency band. Note that an
explanation will be given by assuming a case where this
available frequency band is notified, but it may also be
considered not to perform such notification in a case
where the available frequency band is previously
determined in the communications system.
In the same way as the case of the above
Embodiment 2, the base station transmits pilot signals
Sp, and a terminal transmits the above CQIs calculated
based on the received pilot signals Sp to the base
station. Next, the base station considers the available
frequency band of the terminal, the CQI of each frequency
band transmitted from the terminal, the utilization
situation of the other terminals, the predetermined

transmission rate of the data Du to be transmitted, and
so on and judges if the frequency band must be extended
(used frequency band must be changed) for that terminal.
When extending is needed, the frequency band is
selected. Further, the above timing of change when
extending the used frequency band is selected. Then, the
selection information of this extension band and the
above timing of change are transmitted by using the
control channel. The terminal receiving this control
channel signal changes the setting of each circuit unit
in the terminal based on the information for the
extension band and the timing of change, then starts the
reception by using that extension band.
This operation will be supplementally
explained next. However, refer to the control flow of
FIG. 21 explained before. First, the terminal transmits
the frequency band useable by that terminal to the base
station or its higher base station controller etc. The
base station receiving this transmits pilot channel
signals or pilot signals Sp by using that used frequency
band. Note that when transmitting pilot channel signals
using a common channel common to all terminals, the
selection of the used frequency band is not needed.
The terminal receiving the pilot channel
signals via the frequency bands calculates the above CQIs
based on the above CIRs, SNR, etc., and transmits the CQI
calculated values to the base station through the uplink
control channel. The base station receiving these
considers the CQIs, the utilization situations of the
frequency bands, the predetermined transmission rate of
the transmission data Du, and other QoS, selects the
existence of the necessary for extension and the used
frequency band in the case where the extension is carried
out, determines the timing of change of the band, and
notifies the information to the terminal via the downlink
control channel.
The terminal receiving the information sets or

re-sets each circuit unit of the terminal at the above
timing of change and receives signals by using the
extension band after the change at the above timing of
change.
FIG. 22 is a view showing an example of the
dynamic change of the extension band in the present
Embodiment 3 for easier understanding. The elapse of time
goes from the top toward the bottom in the present
figure. As this elapse of time, the extension band is set
as "BAND 2" → "band 2 + band 3 + band 4" exemplified in
the figure whenever there is a necessity of extension
while selecting a good frequency band next best to the
frequency band having the best propagation environment.
As in the latter case, the expansion band may be set by
combining a plurality of bands.
In this way, the frequency band having a
relatively good propagation environment can be selected
as the extension band for a propagation environment
changing along with the elapse of time. Due to this, the
transmission error of the control channel information is
reduced, the hardware setting of the reception side
becomes easier, and the improvement of the transmission
quality becomes possible. Further, the number of times of
resending the data can be decreased, therefore the
transmission rate can be enhanced. Further, if
considering the processing time for correcting the
settings on the reception side and notifying the change
of the extension band to the other party in advance, the
change of setting described above with respect to the
apparatus becomes easier.
[Embodiment 4: Dynamic change of main band and
extension band]
The characteristic features disclosed in the present
Embodiment 4 will be shown below.
i) Both of the frequency band to be occupied as
the main band among a plurality of frequency bands (band
1 to band 4) and the frequency band to be occupied as an

extension band among those plurality of frequency bands
can be changed along with the elapse of time without
overlap, and
ii) further, one main band and at least one
extension band are simultaneously changed.
FIG. 23 is a flow chart showing an example of
changing both of the main band and an extension band.
In the present figure,
Step S71: Transmit available frequency band.
Step S72: Receive available frequency band, and
Step S73: transmit pilot channel signals using that
available frequency band.
Step S74: Receive all pilot channel signals,
calculate SNRs etc., and convert to CQIs, and
Step S75: transmit above CQIs through uplink control
channel.
Step S76: Receive above CQIs,
Step S77: receive main band, that is, frequency band
having best propagation environment,
Step S78: further, select extension band, that is,
frequency band having second best propagation
environment,
Step S7 9: transmit extended frequency band and its
timing of change through downlink control channel, and
Step S80: select timing of change thereof.
Step S81: Receive above extended frequency band
and timing of change,
Step S82: change setting for each circuit unit at
the timing of change, and
Step S83: start reception operation in extension
band after that change.
Supplementing the explanation for the control
flow of FIG. 23, here, it is assumed that each main band
and each extension band are selected based on a
predetermined transmission rate of the transmission data
Du (see FIG. 24). The frequency band having the best
propagation environment is selected as the main band

based on the above CQIs of the frequency bands
transmitted from the terminal. Then, the frequency band
having the propagation improvement which next best to
that (second) is selected as the extension band. Then,
the timing of change is selected, and these are
transmitted to the other party via the control channel.
The terminal receiving the used frequency band
information (both of the main band and the extension
band) and the change timing information changes the
settings of the reception side circuit unit at this
timing of change, then receives the two signals of the
main band and the extension band.
FIG. 24 is a flow chart showing an example of
the dynamic change of the main band and extension band in
the present Embodiment 4 for easier understanding. The
elapse of time goes from the top toward the bottom in the
figure. Along with that the main band is set as "BAND 1"
→ "BAND 1" → "BAND 3" → "BAND 2" as exemplified in the
present figure, the extension band is set while forming a
pair at either the left or right of the main band (on
left side or right side in the present figure). Note, the
two bands do not always have to form a pair. When looking
at for example the third stage in the figure, there also
exists a case where this extension band (band 4) does not
exist, and when looking at for example the fourth stage
in the figure, this extension band may not exist in the
shown band 3, but may exist in the band 4 on the right
adjacent to that with a space.
From the above description, it becomes possible
to use the frequency bands with the best and second best
propagation environments as the main band and the
extension band. Further, even when the propagation
environment changes along with time, it becomes possible
to select the frequency bands having the best and second
best propagation environments as the main band and the
extension band.
Due to this, in the same way as the above

embodiments, the transmission error of the control
channel information is reduced, the hardware settings on
the reception side become easier, and improvement of the
transmission quality becomes possible. Further, the
number of times of resending the data can be decreased,
therefore the transmission rate can be improved. Further,
by considering the processing time for correcting the
settings on the reception side and notifying the change
of the main band and the extension band to the other
party in advance, the change of the hardware settings
becomes easy.
[Embodiment 5: Selection of main band and extension
band according to propagation environment]
First, the characteristic features disclosed in the
present Embodiment 5 are shown below.
i) Judgment of whether or not the propagation
environment between the communications apparatuses (10,
20) is good is performed individually for each of a
plurality of frequency bands (band 1 to band 4), the
judgment result for each frequency band is individually
transmitted to the communications apparatus of the other
party,
ii) the judgment of whether or not the propagation
environment between the communications apparatuses (10,
20) is good is performed individually for each of a
plurality of frequency bands (band 1 to band 4), the
judgment results for all frequency bands are multiplexed,
and the multiplexed results are transmitted to the
communications apparatus of the other party all together,
and
iii) the above judgment results are transmitted to
the communications apparatus of the other party by using
either the main band, extension band, or frequency band
having a relatively good propagation environment.
In carrying out the present Embodiment 5, the
already explained example of configuration of FIGS. 15A
and 15B can be used or the example of configuration of

FIG. 25 can be used.
FIG. 25 is a view showing an example of the
hardware configuration on the return side of the response
(CQI) information to the pilot signals. The example of
configuration of the present figure is similar to the
example of configuration of FIGS. 15A and 15B described
above. The difference thereof resides in that individual
processing linked with each of a plurality of frequency
bands is carried out in FIG. 15B, but in the lower half
in FIG. 25, CQIs for a plurality of frequency bands are
multiplexed and processed all together. That is, in FIG.
25, the transmission quality (CQI) is transmitted to the
other party by one control channel. For this purpose, a
multiplexing unit (Mux) 80 is introduced into the output
side of the loop back path 77.
In the embodiments explained before, when
transmitting the CQIs of the different frequency bands
from a terminal to the base station, they may be
transmitted through the uplink control channel for each
frequency band or the CQIs for all frequency bands may be
transmitted through the uplink control channel of for
example the main band.
When transmitting the CQIs by using the uplink
control channel for each frequency band, the example of
configuration of FIGS. 15A and 15B is used. Note that, in
the present example of configuration, no description is
made of the uplink transmission data Du, but it is also
possible to multiplex this data Du on the control channel
and transmit the same. Further, the present example of
configuration assumes a case where pilot channel signals
are simultaneously received for a plurality of frequency
bands.
In the terminal shown in FIG. 25, the signal of
each frequency band is received and converted in
frequency corresponding to that frequency band.
Thereafter, the GI is eliminated at the GI elimination
unit 54, a frequency-time transform is applied by the S/P

unit 55, FFT unit 56, and P/S unit 57, then the result is
demodulated at the demodulation unit 23. The propagation
situation is.measured by the SNR, CIR, etc. using this
demodulation signal, then the CQI value is calculated.
The above CQI value calculated for each
frequency band is transmitted through the control channel
of each frequency band. At this time, it is also possible
to transmit the other control channel signal together.
Further, it is also possible to transmit the same
together with the uplink transmission data.
The calculated CQI enters into the part of FIG.
15B by the loop back path 77, is encoded at the encoding
unit 78, modulated at a modulation unit 112, then
subjected to a time-frequency transform at an S/P unit
137, an IFFT unit 138, and a P/S unit 139. Further, the
GI is inserted at a GI insertion unit 140, then the
result is converted to the corresponding frequency band
and transmitted from the antenna AT.
From the above description, it becomes possible
to transmit the CQI (propagation situation) of each
frequency band to the base station in the same way as the
embodiments explained before. Further, it becomes
possible to select the frequency band having a good
propagation environment as the main band based on the
CQIs (propagation situations) sent from the terminal. In
the same way, it becomes possible to select the frequency
band having a relatively good propagation environment as
the extension band. In this way, in the same way as the
embodiments explained before, the transmission
characteristics are improved by using the better
frequency band, and the number of times of resending the
data is decreased, therefore improvement of the
transmission rate becomes possible.
Next, the example of configuration of FIG. 25
described above is employed for a case of transmitting
all CQIs by using the uplink control channel of a
specific frequency band. In the same way as the case of

using the uplink control channel for each frequency band
explained above, the CQI in each frequency band is
calculated. These calculation results are combined into
one at the above multiplexing unit (Mux) 80, then this is
encoded at the encoding unit 78. Further, it is modulated
at the modulation unit 112, then subjected to a time-
frequency transform at the S/P unit 137, IFFT unit 138,
and P/S unit 139 and given a GI at the GI insertion unit
140. Thereafter, the result is converted in frequency by
the circuits 141 and 142 and transmitted from the antenna
AT.
Note that, as the frequency band used for the
transmission of the CQI to be used, the main band which
is selected because of its relatively good transmission
environment may be selected, the frequency band having
the best propagation environment (best CQI) may be
selected, and another frequency band may be selected.
Further, the frequency band previously set as the
communications system may be used.
From the above description, in the same way as
the embodiments explained before, it becomes possible to
transmit the CQI (propagation situation) of each
frequency band to the base station. Further, it becomes
possible to select the frequency band having a good
propagation environment as the main band based on the CQI
(propagation situation) sent from the terminal. In the
same way, it becomes possible to select the frequency
band having a good propagation environment as the
extension band. By selecting the better frequency band in
this way, the transmission characteristics are improved,
the number of times of resending the data is decreased,
and therefore improvement of the transmission rate
becomes possible.
[Embodiment 6: High efficiency transmission of used
frequency band information]
The characteristic feature disclosed in the present
Embodiment 6 is that, for each of a plurality of

frequency bands (band 1 to band 4), at least one of
information (i to iv) of (i) a frequency band
identification number, (ii) used/not yet used as main
band, (iii) used/not yet used as extension band, and (iv)
current status maintained is encoded and transmitted to
the communications apparatus of the other party.
FIG. 26 is a view showing tables for explaining
the high efficiency transmission of the used frequency
band information. Table 1 shows an example of
correspondence of the used frequency band and band
number, and Table 2 and Table 3 show a first example and
a second example of the method of setting of used/not yet
used of the used frequency band.
In the transmission of the above used frequency
band information in the embodiments explained above, for
example, by assigning numbers to frequency bands and
transmitting the numbers, the amount of control channel
information can be reduced in comparison with the case
where the value of frequency per se is transmitted. A
concrete example will be explained by using the above
Table 1 to Table 3. Note that, here, an example where the
frequency band useable by the communications system as a
whole is set to 800 MHz to 820 MHz and this is divided
into four frequency bands as in FIG. 9 for use is shown.
First, band numbers (1, 2, 3, 4) are assigned
to the bands as shown in Table 1. Further, which
frequency band is to be used as the main band, and which
frequency band is to be used (or not used) as the
extension band is set as in Table 2.
At this time, in for example a case where the
band 1 is "not yet used", the band 2 is used as the "main
band", the band 3 is used as the "extension band", and
the band 4 is "not yet used", the following control data
"yyllOOzz" is obtained wherein yy and zz are "01" or
"10".
Note that, here, the above control data was
prepared in a sequence of band 1, band 2, band 3, and

band 4, but this sequence may be any so far as
recognition is possible on the transmission side and the
reception side. Further, the number of bands can be
freely increased or decreased. Further, an explanation
was given here by taking as an example four consecutive
frequency bands, but nonconsecutive frequency bands
having not yet used bands in the middle may also be
employed.
As described above, by encoding information
(forming tables), the amount of information can be
reduced in comparison with for example the case where the
value of the center frequency of the band per is
transmitted.
Further, as shown in Table 3, it is also
possible to provide settings in the case where there is
no change in the usage situation, that is, the case of
"current status maintained".
By encoding (forming tables) the used frequency
band information as described above, the data length of
the control signal can be compressed. Accordingly, the
ratio of the transmission data and the control channel
information is reduced for the latter, and accordingly
the transmission efficiency of the transmission data is
improved.
[Embodiment 7: Continuous setting and nonconsecutive
setting of extension bands]
First, when describing the characteristic features
disclosed in the present Embodiment 7, they are as
follows.
i) One extension band or two or more
consecutive extension bands are assigned as the frequency
bands consecutive to the main band on the frequency axis,
ii) or an isolated extension band not consecutive
with any of the extension bands is further included on
the above frequency axis, and
iii) a signal having no meaning is inserted in the
not yet used frequency band accompanying the above

isolated extension band and transmitted to the
communications apparatus of the other party. Note that as
views representing the present Embodiment 7, there are
FIG. 27 and the already explained FIG. 22.
FIG. 27 is a view showing an example of dynamic
change of the extension band. In contrast to the above
FIG. 22 showing the case where consecutive extension
bands are selected, FIG. 27 shows a case nonconsecutive
extension bands (see the fourth stage of the same
diagram) are selected. Note that the method of viewing
FIG. 27 is exactly the same as the method of viewing the
above FIG. 22. This will be concretely explained below.
First explaining the case where the extension
bands are consecutive, the already explained FIG. 22
shows a case where the extension bands are consecutively
selected. Note as one example, a case where a consecutive
band forming a pair with the main band is selected as the
extension band. In the mode of this FIG. 22, the
extension band is consecutive with the main band,
therefore, in comparison with the case of nonconsecutive
bands (FIG. 27), the signal processing becomes simpler.
Note that the transmission operation and the reception
operation are the same as those explained in the above
embodiments.
On the other hand, FIG. 27, as described above,
also shows a case where an extension band is
nonconsecutive (fourth stage). In this way, it is also
possible to nonconsecutively select an extension band
with respect to the main band or an adjacent extension
band from the used frequency band of the terminal, the
propagation environment, and the balance with other
terminals.
Note that a subcarrier bridging the consecutive
frequency bands (see a dotted line SC of FIG. 22) is not
set in the explanation hitherto, but according to the
usage situation of the other terminals, it is also
possible to set a subcarrier bridging two frequency bands

and increase the amount of transmission information by
that amount.
Further, the reception side terminal does not
receive signals at the above nonconsecutive frequency
bands or forcibly processes the related signals as
meaningless signals. Due to this, even when the extension
bands are non consecutive, reception can be carried out
without problem.
As described above, by setting nonconsecutive
extension bands, it becomes possible to flexibly select
the extension bands considering the used frequency band
of the terminal, the propagation environment, and the
usage situation of the other terminals. Further, due to
this, the efficiency of frequency utilization is further
improved.
[Embodiment 8: Making number of subcarriers in each
frequency band constant]
The characteristic feature disclosed in the present
Embodiment 8 resides in that the bandwidth of each of a
plurality of frequency bands (band 1 to band 4) is set to
a predetermined constant value and the number of the
series of subcarriers in each band is made a
predetermined constant value.
FIG. 28 is a view showing a first example of a
band extension pattern, FIG. 29 is a view showing a
second example of a band extension pattern, and FIG. 30
is a view showing a third example of a band extension
pattern.
Note that the method of viewing these FIG. 28
to FIG. 30 is substantially the same as the method of
viewing the above FIG. 22, FIG. 24, FIG. 27, etc. While
FIG. 22, FIG. 24, FIG. 27, etc. show patterns using
actual waveforms, FIG. 28 to FIG. 30 only show patterns
as blocks of subcarriers in place of such actual
waveforms. This is for facilitating the explanation of
the present Embodiment 8. Namely, they show the concept
of a "frequency band unit" visually for easier

understanding. Note that terms described in FIG. 28 to
FIG. 30 are already explained except a "processing
delay". This processing delay, when viewing for example
FIG. 4, means a time delay required for the processing
from when the used frequency band information If is input
to the used frequency band setting unit 25 to when the
band set instruction signal Sb is generated and further
the parameters finish being set in each circuit part.
In general, in the multicarrier transmission
mode (OFDM, MC-CDMA etc.) or other communication system
using a series of subcarriers, when changing the
bandwidth, ordinarily the change is carried out in units
of subcarriers. In this case, used/not yet used must be
set in unit of subcarriers. Further, in the sending
processing and receiving processing, signal processing
considering "used/not yet used" in unit of subcarriers is
necessary, so the setting of bands is liable to become
troublesome and complex. Further, in a case where the
users are multiplexed, control of used/not yet used of
each subcarrier is necessary between users. As a result,
a drop in the efficiency of frequency utilization is
caused.
Therefore, in the present Embodiment 8, the
used frequency band of the communications system as a
whole is divided into a plurality of bands (band 1 to
band 4), the "number of subcarriers is made constant" in
the divided frequency bands, and transmission between
communications apparatuses is carried out by using one or
more of the frequency bands. Due to this, an improvement
of the efficiency of frequency utilization can be
achieved.
Specifically, for example one frequency band is
set to 5 MHz, and the number of subcarriers in that
frequency band is set to 25. By setting a plurality of
such frequency bands, the above used frequency band is
made variable in units of frequency bands. The above FIG.
28 to FIG. 30 show concrete examples of band extension in

units of bands. An abscissa in each diagram indicates the
bandwidth, one hatched block represents one frequency
band, and a plurality of subcarriers are assumed to be
contained in that one frequency band. In the same way as
FIG. 9, it may be considered that the band 1, band 2,
band 3, and band 4 are arranged from the left.
FIG. 28 shows a case where the band 1 is used
as the main band, and FIG. 29 shows a case where the band
2 is used as the main band. Further, FIG. 30 shows an
example of changing the setting of the extension band
along with the elapse of time and shows a case where
those extension bands include a nonconsecutive one (see
the sixth stage). Note that the concrete operation of
transmission/reception is as explained in the above
embodiments.
From the above description, the used frequency
band can be easily made variable, and it becomes possible
to raise the utilization efficiency of the frequency.
Further, when compared with the case where the used
frequency band is made variable in units of subcarriers,
the above transmission/reception operation becomes
further simpler, and the configuration of a
transmitter/receiver becomes simpler.
[Embodiment 9: Making both number of subcarriers and
subcarrier bandwidth in each frequency band constant]
Describing characteristic features disclosed in the
present Embodiment 9, they are as follows:
i) The bandwidth of each of the plurality of
frequency bands (band 1 to band 4) is made a
predetermined constant value, and the bandwidth of each
subcarrier in each band is made a predetermined constant
value, and
ii) further, also the number of subcarriers is made
a predetermined constant value. Due to this, the main
band and the extension band can be easily set in units of
frequency bands.
In the above Embodiment 8, the number of

subcarriers per band was made constant, but in the
present Embodiment 9, the bandwidth of each subcarrier is
also made constant.
As a result of this, the difference between
bands becomes only the center frequency of each. Due to
this, baseband signal processing is made uniform
irrespective of the frequency band, and, when compared
with Embodiment 8, the configuration of the
transmitter/receiver becomes further simpler.
[Embodiment 10: Setting of band based on difference
between predetermined transmission rate and real
transmission rate]
Describing the characteristic features disclosed in
the present Embodiment 10, they are as follows:
i) In order to judge necessity/unnecessity of
an extension band, the difference between a predetermined
transmission rate S1 assumed to be necessary for the
exchange of information and an actual transmission rate
S2 which is actually achieved (S1 - S2) is calculated. It
is judged whether the extension band is required or not
required in accordance with the positive or negative sign
of this difference, and
ii) here, the above actual transmission rate is
found from the number of the transmission data
information calculated from the number of used frequency
bands and the transmission interval of the transmission
data information.
FIG. 31 is a view showing an example of the
configuration of the communications apparatus
(transmission side) according to Embodiment 10, and FIG.
32 is a flow chart showing an example of the operation in
the apparatus of FIG. 31.
Referring to FIG. 31 first, the figure is
substantially the same as the configuration of the above
FIG. 5 (also FIG. 3 is the same), but differs in the
point that a frequency band selecting/setting unit 85
(modification of 15) and an actual transmission rate

calculation unit 86 shown on the left end in the figure
are introduced.
[0203] Further, referring to FIG. 32, the operation
thereof is:
Step S91: Confirm predetermined transmission rate,
Step S92: confirm amount of transmission data, and
Step S93: calculate actual transmission rate.
[0204] Step S994: Judge whether or not it is necessary
to extend used frequency band based on rate values in
steps S91 and S93 and judge that it is necessary.
[0205] Step S95: Select extended frequency band and
determine timing of change, and
Step S96: transmit that extended frequency band and
its timing of change through downlink control channel.
[0206] Step S97: Receive extended frequency band and
timing of change,
Step S98: change setting of each circuit unit at
that timing of change, and
Step S99: start reception by using extension band
after change.
[0207] Explaining this further concretely, in the
above Embodiment 1, used/not yet used of the extension
band and the number of extension bands were determined
based on only the predetermined transmission rate, but in
the present Embodiment 8, the extension or reduction of
the band is carried out by considering the difference
between the actual transmission rate and the
predetermined transmission rate.
[0208] A concrete example will be explained by using
FIG. 31 and FIG. 32 again. Note that the explanation will
be omitted for the same parts as those in Embodiment 1.
[0209] Assume that a predetermined transmission rate
Rd of a certain transmission data Du is 10 Mbps, and the
transmission is carried out by using the main band and
the extension band. At this time, from the number of
transmission data calculated from the number of used
frequency bands and the transmission interval thereof, an

actual transmission rate Ra can be calculated by an
actual transmission rate calculation unit 86 of FIG. 31.
This actual transmission rate Ra and the predetermined
transmission rate Rd are compared at the above
selecting/setting unit 85. When the actual transmission
rate Ra is lower, the used frequency band is increased
(extended). Further, for example, when is judged that the
predetermined transmission rate Rd can be secured even
when the actual transmission rate Ra is much higher than
the predetermined transmission rate Rd and the used
frequency band is decreased, the used frequency band is
decreased (reduced).
From the above description, an improvement of
the efficiency of frequency utilization can be achieved
while satisfying the predetermined transmission rate.
Note that, other than the above method, it is also
possible to ask the base station to return whether or not
the data transmitted from the base station could be
transmitted to the terminal (ACK/NACK), calculate the
actual transmission rate based on that, and make the used
frequency band variable. Further, it is also possible to
calculate the transmission rate based on the amount of
data transmitted from the base station to the terminal,
ask the terminal to return this transmission rate value
to the base station, and make the used frequency band
variable based on that value.
[Embodiment 11: Enlargement of used frequency band]
FIG. 33 is a view for explaining the present
Embodiment 11. The parts to be particularly noted are a
"restricted band" and a "overall frequency band after
lifting restriction". Here, the characteristic features
disclosed in the present Embodiment 11 are as described
below:
i) In a communications system for exchange of
information between communications apparatuses (10, 20)
by the multicarrier transmission mode using a series of
subcarriers, in a case where the usage of only a part of

the divided frequency bands ("band a") is permitted at
present among a plurality of divided frequency bands
(band a to band d) formed by dividing the overall
frequency band to be assigned to this communications
system in the future (see "overall frequency band after
lifting restriction" of FIG. 33) (see "restricted band"),
that divided frequency band "band a" allowed to be used
is operated further divided into one or more frequency
bands (like band 1 to band 4 in Embodiments 1 to 10). At
the same time, each of the other divided frequency bands
which are restricted at present (band b, band c, and band
d) is divided into one or more frequency bands in the
same way as the former (like band 1 to band 4 in
Embodiments 1 to 10) in advance. Then, when the
restriction is lifted in the future, each of the
plurality of divided frequency bands (band b to band d)
which are formed by dividing the overall frequency band
but not yet used at present is immediately operated by
the same operation as the operation of dividing the
divided frequency band (band a) allowed to be used at
present into one or more frequency bands, and
ii) here, the plurality of frequency bands (band a
to band d) formed by dividing the overall frequency band
have constant bandwidths with respect to each other, and
the number and bandwidth of subcarriers in each of those
divided frequency bands have constant values with respect
to each other.
Explaining this further concretely, there may
be cases where frequency band usable by the present
communications system (or base station) is restricted
from the balance with other communications system but
later the restriction is lifted for a reason that the
frequency used by the other communications system is
shifted elsewhere and so on.
When assuming such case, the above limited used
frequency band ("limited band a") is operated by dividing
the band (a) into one or more frequency bands in the same

way as the above embodiments. Then, at this time, the
restricted frequency bands (band b, band c, and band d)
are individually divided to one or more frequency bands
as well. Note that preferably the used frequency band
(band a) and restricted frequency bands (bands b to d)
are divided with the same bandwidth. FIG. 33 assumes
division with the same bandwidth in this way. Further, in
FIG. 33, the used frequency band is limited to the "band
a" which is operated as a single frequency band. The
whole restricted frequency band is divided into three
bands (band b to band d), but these bands b to d can not
be used at present due to the restrictions. Note that the
number of subcarriers and the subcarrier bandwidth of
each of these bands are constant.
Note that, while restricted, the frequency band
is set as a single band (band a), therefore the used
frequency band cannot be extended. According to the
present Embodiment 11, after the lifting of the
restriction described above, the number of used frequency
bands becomes four (bands a to d), and the operation can
be immediately shift to the operation of the embodiments
explained before.
By setting the frequency band as described
above, the used frequency band is limited at present, but
when the restriction is lifted after that, the operation
can be immediately shifted to the system operation
according to the present invention. This enables the
flexible operation of the communications system.
As explained in detail above, according to the
present invention, it becomes possible to easily make the
used frequency bandwidth variable, and due to this, the
utilization efficiency of the frequency can be much
enhanced.

WE CLAIM:
1. A communications apparatus accommodated in a communications system for exchange of
information between communications apparatuses (10, 20) by a multi-carrier transmission
mode using a series of subcarriers, the communications apparatus comprising,
a setting unit (15) for setting a specific frequency band from among a plurality of frequency
bands assigned to the communications system, and
a transmission unit (13) for transmitting used frequency band information, the used frequency
band information determines which remaining frequency band is to be used for communications
between said communications apparatuses (10, 20), and the used frequency band information
is transmitted by the use of the specific frequency band set by said setting unit (15).
2. A communications apparatus as claimed in claim 1, wherein said specific frequency band is
set as a main band in said overall frequency band, and the main band transmits also data
information in addition to said used frequency band information.
3.A communications apparatus as claimed in claim 2, wherein at least one frequency band set
from among said plurality of frequency bands other than said main band is defined' as an
extension band, and the extension mainly transmits further data information.
4.A communications apparatus as claimed in claim 2, wherein said main band is set fixedly at
the time of an establishment of a wireless channel between said communications apparatuses
(10, 20).

5. A communications apparatus as claimed in claim 2, wherein when there are plurality of said
communications apparatuses (10, 20), said main bands are individually set for said plurality of
frequency bands and, at the same time, each of the main bands is assigned corresponding to
each of the plurality of communications apparatuses (10, 20).
6. A communications apparatus as claimed in claim 5, wherein two or more of said
communications apparatuses (10, 20) simultaneously use the same main band by time division
multiplexing and/or code division multiplexing.
7. A communications apparatus as claimed in claim 3, wherein the number of said extension
bands is changed in accordance with a predetermined transmission rate of said data
information.
8. A communications apparatus as claimed in claim 2, wherein a frequency band to be occupied
as said main band among said plurality of frequency bands is made variable along with time.
9.A communications apparatus as claimed in claim 8, wherein whether or not a propagation
environment between said communications apparatuses (10, 20) is good is judged, and a
frequency band having the best propagation environment among said plurality of frequency
bands or a frequency band which is next best to this is selected and set as said main band.

10. A communications apparatus as claimed in claim 9, wherein at the time of a new setting of
said main band, a change of the frequency band thereof is notified to the communications
apparatus of the other party.
11. A communications apparatus as claimed in claim 9, wherein whether or not said
propagation environment is good is judged by using a detection result of transmission quality
obtained in response to a transmitted pilot channel or pilot signal between said communications
apparatuses (10, 20).
12. A communications apparatus as claimed in claim 11, wherein said judgment or whether or
not the propagation environment is good is sequentially or simultaneously carried out for all of
said plurality of frequency bands.
13. A communications apparatus as claimed in claim 9, wherein the result of judgment of
whether or not said propagation environment is good is transmitted to the communications
apparatus of the other party through a control channel of a specific frequency band.
14. A communications apparatus as claimed in claim 3, wherein the frequency band set as said
extension band among said plurality of frequency bands is made variable along with time.
15. A communications apparatus as claimed in claim 14, wherein whether or not the
propagation environment between said communications apparatuses (10, 20) is good is judged,
and the frequency band which is next best to the frequency band having the best propagation
environment among said plurality of frequency bands is selected and set as said extension
band.

16. A communications apparatus as claimed in claim 14, wherein at the time of the
establishment of the wireless channel, the frequency band usable by the communications
apparatus is restricted, and said main band and extension band are dynamically assigned within
that restricted frequency band.
17. A communications apparatus as claimed in claim 15, wherein the setting information of the
frequency band to be set as said extension band is notified to the communications apparatus of
the other party in advance for the extension.
18. A communications apparatus as claimed in claim 16 or 17, wherein frequency band setting
information concerning an extendable or changeable frequency band is received from the
communications apparatus of the other party for the change of said extension band or main
band.
19.A communications apparatus as claimed in claim 18, wherein change timing information
concerning the timing of said change is further received.
20. A communications apparatus as claimed in claim 15, wherein the result of judgment of
whether or not said propagation environment is good is transmitted to the communications
apparatus of the other party through a control channel of a specific frequency band.

21. A communications apparatus as claimed in claim 15, wherein the judgment of whether or
not said propagation environment is good is carried out by using the detection result of
transmission quality returned in response to a pilot channel or pilot signal sent between said
communications apparatuses (10, 20).
22. A communications apparatus as claimed in claim 14, wherein a necessity of setting or
change of said extension band is judged based on at least one of the available frequency band
of the communications apparatus, quality of the propagation environment at each said
frequency band, usage situation of each frequency band, and a predetermined transmission
rate of said data information.
23. A communications apparatus as claimed in claim 15, wherein at the time of new setting of
said extension band, the change of the frequency band thereof is notified to the
communications apparatus of the other party in advance.
24. A communications apparatus as claimed in claim 3, wherein both of the frequency band to
be occupied as said main band among said plurality of frequency bands and the frequency band
to be occupied as said extension band among the plurality of frequency bands are made
variable along with time so that the two will not overlap.
25. A communications apparatus as claimed in claim 24, wherein one of said main band and at
least one said extension band are simultaneously changed.

26. A communications apparatus as claimed in claim 9 or 15, wherein the judgment of whether
or not said propagation environment between said communications apparatuses (10, 20) is
good is individually carried out for each of said plurality of frequency bands, and the judgment
result thereof is individually transmitted to the communications apparatus of the other party for
each frequency band.
27. A communications apparatus as claimed in claim 9 or 15, wherein the judgment of whether
or not said propagation environment between said communications apparatuses (10, 20) is
good is individually carried out for each of said plurality of frequency bands, and judgment
results for all frequency bands are multiplexed and transmitted to the communications
apparatus of the other party all together.
28. A communications apparatus as claimed in claim 26 or 27, wherein said judgment result is
transmitted to said communications apparatus of the other party by using either of said main
band, said extension band, or said frequency band having a good propagation environment.
29. A communications apparatus as claimed in claim 3, wherein, for each of said plurality of
frequency bands, at least one of information of a frequency band identification number,
used/not yet used state as said main band, used/not yet used state of said extension band, and
current status maintained is encoded and transmitted to the communications apparatus of the
other party.

30.A communications apparatus as claimed in claim 3, wherein one said extension band or two
or more continuous extension bands are assigned to a frequency band consecutive with said
main band along a frequency axis.
31.A communications apparatus as claimed in claim 30, wherein an isolated extension band not
consecutive with any of said extension bands is further included on said frequency axis.
32.A communications apparatus as claimed in claim 31,wherein a meaningless signal is inserted
for a not yet used frequency band accompanied with said isolated extension band and
transmitted to the communications apparatus of the other party.
33.A communications apparatus as claimed in claim 3, wherein bandwidths of said plurality of
frequency bands are made a predetermined constant value, and also numbers of said series of
subcarriers in each of the bands are made a predetermined constant value.
34.A communications apparatus as claimed in claim 3, wherein bandwidth of each of said
plurality of frequency bands is made a predetermined constant value, and also bandwidth of
each of said subcarriers in each of the bands is made a predetermined constant value.
35.A communications apparatus as claimed in claim 34, wherein the number of said subcarriers
in each said band is made a predetermined constant value.

36. A communications apparatus as claimed in claim 3, wherein in order to judge necessity of
said extension band, a difference between a predetermined transmission rate SI assumed to be
necessary for the exchange of said information and an actual transmission rate S2 which is
actually achieved (Si - S2) is calculated, and it is judged whether the extension band is required
or not required in accordance with a positive or negative sign of this difference.
37.A communications apparatus as claimed in claim 36, wherein said actual transmission rate is
found from the number of transmission data information calculated from the number of used
frequency bands and a transmission interval of the transmission data information.
38. A method of exchanging information in a communications system, between communications
apparatuses (10, 20) by a multicarrier transmission mode using a series of subcarriers, wherein,
in a case where usage of only a part of divided frequency bands is allowed at present among a
plurality of divided frequency bands formed by dividing an overall frequency band to be
assigned to the communications system in the future, the divided frequency band allowed to be
used at present is operated by further dividing into one or more frequency bands, and each of
the remaining said divided frequency bands restricted at present is divided into one or more
frequency bands as well, and when the restriction thereof is lifted in the future, each of said
plurality of divided frequency bands formed by dividing said overall frequency band but not yet
used at present is immediately operated by the same operation as dividing the divided
frequency band already allowed for use into one or more frequency bands.

39. The method as claimed in claim 38, wherein a plurality of divided frequency bands'formed
by dividing said overall frequency band have constant bandwidths with respect to each other,
and the number and bandwidth of said subcarriers in each of the divided frequency bands have
constant values with respect to each other.



ABSTRACT


TITLE: 'A COMMUNICATION APPARATUS AND A METHOD IN A
COMMUNICATIONS SYSTEM FOR EXCHANGE OF INFORMATION
BETWEEN COMMUNICATIONS APPARATUSES'
The invention relates to a communications system for communications by a
multicarrier transmission mode between a plurality of communications
apparatuses (10, 20) wherein an overall frequency band assigned to the
communications system is divided into a plurality of frequency bands each
having a constant bandwidth (for example band 1 to band 4) and a specific band
(for example band 1) among these divided bands is used to transmit used
frequency band information and thereby determine the assignment of the
remaining bands (band 2 to band 4) to be used between said communications
apparatuses. Here, the specific band is defined as a main band for transmitting
control channel information including said used frequency band information and
also data channel information. The main band may also be added with an
extension band for transmitting further data channel information. Further, the
main band and extension band can be changed in the frequency band used
along with time or can be changed in the number thereof. Both of the main band
and the extension bands are preferably used by multiplexing by some of
communications apparatuses.

Documents:

01570-kolnp-2007-abstract.pdf

01570-kolnp-2007-claims.pdf

01570-kolnp-2007-correspondence others 1.1.pdf

01570-kolnp-2007-correspondence others 1.2.pdf

01570-kolnp-2007-correspondence others 1.3.pdf

01570-kolnp-2007-correspondence others.pdf

01570-kolnp-2007-description complete.pdf

01570-kolnp-2007-drawings.pdf

01570-kolnp-2007-form 1.pdf

01570-kolnp-2007-form 18.pdf

01570-kolnp-2007-form 2.pdf

01570-kolnp-2007-form 3.pdf

01570-kolnp-2007-form 5.pdf

01570-kolnp-2007-gpa.pdf

01570-kolnp-2007-international publication.pdf

01570-kolnp-2007-international search report.pdf

01570-kolnp-2007-pct request.pdf

01570-kolnp-2007-priority document.pdf

1570-KOLNP-2007-(08-02-2013)-ANNEXURE TO FORM-3.pdf

1570-KOLNP-2007-(08-02-2013)-CORRESPONDENCE.pdf

1570-KOLNP-2007-(09-09-2013)-ANNEXURE TO FORM 3.pdf

1570-KOLNP-2007-(09-09-2013)-CLAIMS.pdf

1570-KOLNP-2007-(09-09-2013)-CORRESPONDENCE.pdf

1570-KOLNP-2007-(09-09-2013)-OTHERS.pdf

1570-KOLNP-2007-(19-09-2012)-CORRESPONDENCE.pdf

1570-KOLNP-2007-(23-07-2012)-CORRESPONDENCE.pdf

1570-KOLNP-2007-(27-02-2012)-ABSTRACT.pdf

1570-KOLNP-2007-(27-02-2012)-AMANDED CLAIMS.pdf

1570-KOLNP-2007-(27-02-2012)-DESCRIPTION (COMPLETE).pdf

1570-KOLNP-2007-(27-02-2012)-DRAWINGS.pdf

1570-KOLNP-2007-(27-02-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

1570-KOLNP-2007-(27-02-2012)-FORM-1.pdf

1570-KOLNP-2007-(27-02-2012)-FORM-2.pdf

1570-KOLNP-2007-(27-02-2012)-FORM-3.pdf

1570-KOLNP-2007-(27-02-2012)-OTHERS.pdf

1570-KOLNP-2007-(27-02-2012)-PETITION UNDER RULE 137.pdf

1570-KOLNP-2007-CANCELLED PAGES.pdf

1570-KOLNP-2007-CORRESPONDENCE 1.1.pdf

1570-KOLNP-2007-CORRESPONDENCE.pdf

1570-KOLNP-2007-EXAMINATION REPORT.pdf

1570-KOLNP-2007-FORM 18.pdf

1570-KOLNP-2007-FORM 26.pdf

1570-KOLNP-2007-GRANTED-ABSTRACT.pdf

1570-KOLNP-2007-GRANTED-CLAIMS.pdf

1570-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

1570-KOLNP-2007-GRANTED-DRAWINGS.pdf

1570-KOLNP-2007-GRANTED-FORM 1.pdf

1570-KOLNP-2007-GRANTED-FORM 2.pdf

1570-KOLNP-2007-GRANTED-FORM 3.pdf

1570-KOLNP-2007-GRANTED-FORM 5.pdf

1570-KOLNP-2007-GRANTED-SPECIFICATION-COMPLETE.pdf

1570-KOLNP-2007-INTERNATIONAL PUBLICATION.pdf

1570-KOLNP-2007-INTERNATIONAL SEARCH REPORT & OTHERS.pdf

1570-KOLNP-2007-OTHERS.pdf

1570-KOLNP-2007-PETITION UNDER RULE 137.pdf

abstract-01570-kolnp-2007.jpg


Patent Number 257400
Indian Patent Application Number 1570/KOLNP/2007
PG Journal Number 40/2013
Publication Date 04-Oct-2013
Grant Date 30-Sep-2013
Date of Filing 03-May-2007
Name of Patentee FUJITSU LIMITED
Applicant Address 1-1, KAMIKODANAKA 4-CHOME, NAKAHARA-KU, KAWASAKI-SHI, KANAGAWA
Inventors:
# Inventor's Name Inventor's Address
1 ODE TAKAYOSHI C/O. FUJITSU LIMITED 1-1, KAMIKODANAKA 4-CHOME, NAKAHARA-KU, KAWASAKI-SHI, KANAGAWA 211-8588
2 KAWABATA Kazuo C/O FUJITSU LIMITED1-1, KAMIKODANAKA 4-CHOME,NAKAHARA-KU, KAWASAKI-SHI, KANAGAWA 211-8588
3 KAWASAKI YOSHIHIRO C/O FUJITSU LIMITED 1-1, KAMIKODANAKA 4-CHOME, NAKAHARA-KU, KAWASAKI-SHI, KANAGAWA 211-8588
PCT International Classification Number H01J 11/00
PCT International Application Number PCT/JP04/016154
PCT International Filing date 2004-10-29
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA