1. A point -to-point radio system, comprising: first and second communication apparatuses configured to be respectively connected to first and second antennas and to perform communication 5 through the first and second antennas, the first and second antennas being respectively attached to first and second structures; and control means for adjust ing, based on a quality index related to mechanical vibrations of at least one of the first and second structures, a radio communication parameter to be appl ied to the communicat ion.

2. The point -to-point radio system according to Claim 1, wherein the radio communication parameter comprises at least one of a modulation scheme, a code rate, transmission power, transmission beam width, and reception beam width.

3. The point -to-point radio system according to Claim 1 or 2, further comprising detection means for directly or indirectly detect ing the mechanical vibration, 20 wherein the quality index is calculated based on a detection result by the detection means.

4. The point -to-point radio system according to Claim 3, wherein the detection means directly measures the mechanical vibrations using a vibrat ion sensor coupled to the first antenna, the second antenna, the f irst structure, or the second structure.

5. The point -to-point radio system according to Claim 3, wherein the detection means indirectly measures the mechanical vibrations based on fluctuations in communication quality regarding the communication .

6. A communication apparatus comprising: an antenna attached to a structure; communicat ion means electrically connected to the antenna; and control means for control ling, based on a qual ity index indicating communicat ion quality related to vibrations of the structure, a radio communicat ion parameter to be applied to the communication means.

7. The communication apparatus according to Claim 6, 5 wherein the radio communicat ion parameter comprises at least one of a modulation scheme, a code rate, transmission power, transmission beam width, and reception beam width .

8. The communication apparatus according to Claim 6 or 7, further comprising detection means for directly or indirectly detect ing the vibration, wherein the quality index is calculat ed based on a detection result by the detection means.

9. The communication apparatus according to Claim 8, wherein the detection means directly measures the vibrat ions using a vibrat ion sensor coupled to the antenna or the structure.

10. The communication apparatus according to Claim 8, wherein the detection means indirectly measures the mechanical vibrations based on fluctuations in communication quality regarding the communication .

11. A communication control method for a point -to-point radio communicat ion, the method comprising: performing communication through an antenna attached to a structure; and control ling, based on mechanical vibrations of the structure, a radio communicat ion parameter to be applied to the communication.

12. A non-transitory computer readable medium storing a program for causing a computer to perform a communication control method for a 30 point -to-point radio communication through an antenna attached to a structure, wherein the communication control method includes adjusting, based on mechanical vibrations of the structure, a radio communication parameter to be appl ied to the communication.

13. A point -to-point radio system, comprising: first and second communication apparatuses configured to be respectiv ely connected to first and second antennas and to perform communication through the first and second antennas, the first and second antennas being respectively attached to first and second 5 structures; and control means for adjusting, based on a first qual ity index related to propagat ion characteristics of a radio link and a second quality index related to mechanical vibrations of at least one of the first and second structures, a radio communicat ion parameter to be applied to the communication .

14. The point-to-point radio system according to Claim 13, wherein the radio communication parameter comprises at least one of a modulation scheme, a code rate, transmission power, transmission beam width, and reception beam width.

15. The point -to-point radio system according to Claim 13 or 14, further comprising detection means for directly or indirectly detect ing the mechanical vibration, wherein the second quality index is calculated based on a detection result by the detection means.

16. The point-to-point radio system according to Claim 15, wherein the detection means directly measures the mechanical vibrations using a vibrat ion sensor coupled to the first antenna, the second antenna, the first structure, or the second structure.

17. The point-to-point radio system according to Claim 15, wherein the detection means indirectly measures the mechanical vibrations based on fluctuations in communication quality regarding the communication .

18. A communication apparatus that performs a point -to-point radio communicat ion, the communication apparatus comprising: communicat ion means connected to an antenna attached to a structure; and control means for adjusting, based on a first quality index related to propagat ion characteristics of a radio link and a second quality index related to mechanical vibrations of the structure, a radio communication parameter to be appl ied to the communication.

19. The communication apparatus according to Claim 5 18, wherein the radio communication parameter comprises at least one of a modulation scheme, a code rate, transmission power, transmission beam width, and reception beam width.

20. A communication control method for a point -to-point radio communicat ion, the method comprising: performing communication through an antenna attached to a structure; and adjusting, based on a first quality index related to propagat ion characteristics of a radio link and a second index related to mechanical vibrat ions of the structure, a radio communication parameter to be appl ied to the communicat ion.

21. A non-transitory computer readable medium that stores a program for causing a computer to perform a communication control method for a point -to-point radio communication through an antenna attached to a structure, wherein the communication control method includes adjusting, based on a first qual ity index related to propagation characteristics of a radio link and a second index related to mechanical vibrations of the structure, a radio communicat ion parameter to be applied to the communication.

DESCRIPTION
POINT-TO-POINT RADIO SYSTEM, COMMUNICATION APPARATUS,
AND COMMUNICATION CONTROL METHOD
5
Technical Field
[0001]
The present application relates to an adapt ive adjustment of a modulation
scheme, a code rate and the like in a point -to-point radio system.
10 Background Art
[0002]
Point-to-point radio systems using microwaves, millimeter waves or the
like are known (see, for example, Patent Literature 1). In a point-to-point radio
system, two communication apparatuses perform digi tal communication via a
15 point -to-point radio l ink. Specifically, the two communication apparatuses are
equipped with directional antennas and form directed beams toward each other .
In this way, the point -to-point radio link is establ ished between the two
communicat ion apparatuses.
[0003]
20 Communication quali ty of the point -to-point radio link depends on
meteorological condi tions (e.g., rain, fog, and haze). This is because rain, fog,
haze or the like degrades line-of-sight visibility between the two communication
apparatuses and attenuates radio signals (e.g., microwaves or millimeter waves).
Therefore, the point -to-point radio system performs adaptive processing including
25 adjusting a modulation scheme, a code rate and the like based on the
communicat ion quality (e.g., received signal strength (received signal strength
indicator (RSSI)), a signal to noise ratio (SNR), or a bi t error rate (BER)) of the
point -to-point radio l ink. Patent Li terature 1 and 2 disclose this adaptive
processing. The adaptive processing that adjusts a modulation scheme, a code
30 rate and the like based on communication qual ity of a radio link is called "adaptive
modulation and coding (AMC) " or "link adaptation".
[0004]
Point-to-point radio systems are used, for example, in a mobile backhaul .
The mobile backhaul means communication lines that connect base stations of a
3
cellular communication system to a core network and communication lines that
connect base stations. Compared to wired connections using optical fibers,
point -to-point radio systems have many advantages, such as easy networking, low
costs, and mitigat ion of conditions for an instal lation location of a base station.
5 Citation List
Patent Literature
[0005]
[Patent Literature 1] European Patent No. 1545037
[Patent Literature 2] Japanese Unexamined Patent Application Publication No.
10 2005-94605
Summary of Invention
Technical Problem
[0006]
In the cellular communication system, small cells each having coverage of
15 several tens to several hundreds of meters are mainly used in urban areas to
increase communication capacity, enhance communicat ion speed, and compensate
for coverage holes. The small cells may be called pico cells or femto cells.
[0007]
When a point-to-point radio system is used as a mobi le backhaul for a
20 small -cell base station, a new problem stated below may occur. The small-cell
base stat ion may be located in a place nearer a street level (e.g. , a lamp post and a
bus shelter) compared to a macrocell base stat ion. In this case, similar to the
small -cell base station, a point -to-point radio communication apparatus may also
be installed in the lamp post, the bus shel ter and the like. However, the lamp
25 post, the bus shelter and the like can be easily deformed and mechanically vibrated
by an external force such as wind, vibrations caused by a subway, and an
earthquake. These mechanical vibrations may not be a big problem for the
small -cell base station. On the other hand, since the point -to-point radio
communicat ion apparatus communicates with the opposing apparatus using a
30 directed beam toward the opposing apparatus, the mechanical vibrations may cause
fluctuations in the direction of the antenna and degrade the communicat ion quality
significantly.
[0008]
The present invention has been made in view of the aforement io ned
4
discussion by the present inventor and aims to provide a point-to-point radio
system, a communication apparatus , a communication control method, and a
program that contribute to suppressing degradation of communication quality of a
radio l ink which occurs due to mechanical vibrations of a structure to which a
point -to-point radio communication apparatus 5 i s at tached.
Solution to Problem
[0009]
In a first aspect, a point -to-point radio system includes first and second
communicat ion apparatuses and a control unit . The first and second
10 communicat ion apparatuses are configured to be respectively connected to first
and second antennas and to perform communication through the first and second
antennas. The first and second antennas are respectively at tache d to first and
second structures. The control unit is configured to adjust , based on a quality
index related to mechanical vibrations of at least one of the first and second
15 structures, a radio communicat ion parameter to be applied to the communication .
[0010]
In a second aspect, a communicat ion apparatus for a point-to-point radio
communicat ion includes an antenna, a communicat ion unit , and a control unit .
The communication unit is connected to the antenna attached to a structure. The
20 control unit is configured to adjust , based on a qual ity index indicating
communicat ion quality related to vibrations of the structure, a radio
communicat ion parameter to be applied to the communication.
[0011]
In a third aspect, a communication control method for a point-to-point
25 radio communication includes: performing communication through an antenna
attached to a structure; and controlling, based on mechanical vibrations of the
structure, a radio communicat ion parameter to be applied to the communication.
[0012]
In a fourth aspect, a program includes instructions to cause a computer to
30 perform the method according to the third aspect stated above.
[0013]
In a fifth aspect, a point -to-point radio system includes first and second
communicat ion apparatuses and a control unit . The first and second
communicat ion apparatuses are configured to be respectively connected to first
5
and second antennas and to perform communication through the first and second
antennas. The first and second antennas are respectively at tached to first and
second structures. The control unit is configured to adjust , based on a first
qual ity index related to propagation characteristics of a radio link and a second
qual ity index related to mechanical vibrations of at least one 5 of the first and
second structures, a radio communication parameter to be appl ied to the
communicat ion.
[0014]
In a sixth aspect , a communication apparatus for a point -to-point radio
10 communicat ion includes a communication unit and a control uni t. The
communicat ion unit is connected to an antenna attached to a structure . The
control unit is configured to adjust , based on a first qual ity index related to
propagat ion characteristics of a radio link and a second quality index related to
mechanical vibrations of the structure, a radio communication parameter to be
15 appl ied to the communication.
[0015]
In a seventh aspect, a communication control method for a point-to-point
radio communication includes: performing communication through an antenna
attached to a structure; and adjust ing, based on a first quality index related to
20 propagat ion characteristics of a radio link and a second index related to
mechanical vibrations of the structure, a radio communication parameter to be
appl ied to the communication.
[0016]
In an eighth aspect , a program includes instructions to cause a computer to
25 perform the method according to the seventh aspect stated above.
Advantageous Effects of Invention
[0017]
According to the aspects stated above, it is possible to provide a
point -to-point radio system, a communicat ion apparatus, a communication control
30 method, and a program that contribute to suppressing degradation of
communicat ion quality of a radio l ink which occurs due to mechanical vibrations
of a structure to which a point -to-point radio communicat ion apparatus is attached.
Brief Description of Drawings
[0018]
6
Fig. 1 is a block diagram showing a configuration example of a
point -to-point radio system according to a first embodiment;
Fig. 2 is a diagram showing mechanical vibrat ions of a structure to which a
point -to-point radio antenna is attached;
Fig. 3 is a frequency distribution diagram indicating 5 degradation of
communicat ion quality caused by mechanical vibrations of a structure to which a
point -to-point radio antenna is attached;
Fig. 4 is a flowchart showing one example of an adaptive control
procedure in the point -to-point radio system according to the first embodiment;
10 Fig. 5 is a block diagram showing a configuration example of a
communicat ion apparatus according to a second embodiment;
Fig. 6 is a flowchart showing one example of an adaptive control
procedure in a point -to-point radio system according to the second embodiment;
Fig. 7 is a block diagram showing a configuration example of a
15 communicat ion apparatus according to a third embodiment ;
Fig. 8 is a flowchart showing one example of an adaptive control
procedure in a point -to-point radio system according to the third embodiment; and
Fig. 9 is a flowchart showing one example of an adaptive control
procedure in a point -to-point radio system according to a fourth embodiment .
20 Description of Embodiments
[0019]
Hereinafter, with reference to the drawings, specific embodiments will be
described in detail. Throughout the drawings, identical or corresponding
components are denoted by the same reference symbols, and overlapping
25 descriptions will be omitted as appropriate for the sake of clarification of
description.
[0020]
First embodiment
Fig. 1 shows a configuration example of a point -to-point radio system
30 according to this embodiment . The point -to-point radio system according to this
embodiment includes communication apparatuses 1 and 2. The communication
apparatuses 1 and 2 include antennas 10 and 20, respectively. The antennas 10
and 20 are directional antennas. The communicat ion apparatuses 1 and 2 form
directed beams toward each other to establ ish a pint-to-point radio link 50 between
7
the antennas 10 and 20, and transmit signals at least in one direction between them
via the radio link 50. In the specific example shown in Fig. 1, the communication
apparatuses 1 and 2 include transceivers 11 and 21, respectively, and transmit
signals bidirectionally via the radio link 50.
5 [0021]
The communication apparatuses 1 and 2 further include controllers 12 and
22, respectively. Each of the controllers 12 and 22 performs adapt ive processing
to maintain communication quality (e.g., received signal strength, SNR, or BER)
of the point-to-point radio l ink 50. The controllers 12 and 22 may perform, as
10 stated in the Background Ar t, AMC (or link adaptation) that changes a modulation
scheme, a code rate and the like according to the communication quality of the
radio l ink 50 to deal with changes in a propagation state according to
meteorological condi tions (e.g., rain, fog, mist, haze, smoke, or smog).
[0022]
15 Further, each of the controllers 12 and 22 adjusts a radio communication
parameter (e.g. , one or both of the modulation scheme and the code rate) based on
mechanical vibrations of the antenna 10 or 20 in order to compensate f or
degradation of the communicat ion quality of the radio link 50 due to mechanical
vibrations of the antenna 10 or 20. In other words, each of the control lers 12 and
20 22 adjusts the radio communication parameter based on a qual ity index related to
mechanical vibrations of a structure to which the antenna 10 or 20 is attached.
The mechanical vibrations of the structure to which the antenna 10 or 20 is
attached are conducted to the antenna 10 or 20. Accordingly, i t can also be said
that each of the controllers 12 and 22 adjusts the radio communication parameter
25 based on a quality index related to mechanical vibrat ions of the antenna 10 or 20.
[0023]
The quality index related to mechanical vibrations of a structure may
include measurement values indicating displacement , velocity, or acceleration of
the structure to which the antenna 10 or 20 is attached. The measurement values
30 may be obtained by a vibrat ion sensor coupled to the structure to which the
antenna 10 or 20 is at tached. Al ternatively, the quali ty index related to
mechanical vibrations of a structure may include a statist ical value (e.g. , standard
deviation or dispersion) indicating fluctuations in the communication quality (e.g.,
RSSI, SNR, or BER) of the radio link 50.
8
[0024]
In the following description, an influence of mechanical vibrations of the
antennas 10 and 20 on the communication qual ity of the radio l ink 50 and details
of the adaptive processing to compensate for this influence will be described.
Fig. 2 shows a specific example of mechanical vibrat ions of the 5 structure to which
the antenna 10 is attached. In the example shown in Fig. 2, the antenna 10 is
fixedly attached to the structure 40 (e.g. , a lamp post or a bus shelter). Not only
the antenna 10, but the communication apparatus 1 including the antenna 10 and
the transceiver 11 may be attached to the structure 40. Further, when the
10 communicat ion apparatus 1 is used for a mobile backhaul of a small -cell base
station, the communication apparatus 1 and the small -cel l base station may be
attached to the structure 40. Furthermore, besides the communication apparatus 1
and the small -cel l base stat ion, a data transfer apparatus may be attached to the
structure 40. The data transfer apparatus transfers data packets (e.g., Internet
15 Protocol ( IP) packets) or data frames (e.g. , Media Access Control (MAC) frames)
between the communication apparatus 1 and the small -cell base station. The data
transfer apparatus is, for example, a router, a layer -3 switch, or a layer -2 switch.
[0025]
The structure 40 is deformed and mechanically vibrated due to an external
20 force such as wind, vibrations caused by a subway, and an earthquake. The
vibrations of the structure 40 cause mechanical vibrat ions of the antenna 10.
Since the antenna 10 forms a directed beam 51 toward the antenna 20 of the
communicat ion apparatus 2 for communication, mechanical vibrations of the
antenna 10 may cause fluctuations in the direction of the antenna 10 (i.e. , directed
25 beam 51) and, accordingly, significantly degrade the communication quality of the
radio l ink 50.
[0026]
The AMC to deal wi th changes in the propagation state according to the
meteorological condi tions, which is described in the Background Art, may only
30 need to be performed in accordance with speed of changes in weather .
Specifically, the modulation scheme, the code rate and the like may be changed
according to a magnitude of an average of measurement values of the
communicat ion quality of the radio link (e.g., RSSI, SNR, or BER) observed wi th a
long t ime scale corresponding to speed of changes in weather (e.g., observed at
9
intervals of from one minute to one hour ). The reason for using the average value
of the communication quality is to avoid following sudden short -time fluctuations
in the communication quality.
[0027]
On the other hand, vibration frequency and vibration 5 period of the
structure 40 are determined according to the natural frequency and the natural
period of the structure 40. The natural frequency of the structure such as the
lamp post , the bus shelter and the like is considered to be in a range of about 0.1
Hz to about 20 Hz, and typically in a range of about 1 Hz to about 10 Hz. The
10 natural period of these structures is in a range of about 0.05 second to about 10
seconds, and is typically in a range of about 0.1 second to about 1 second.
Therefore, the vibration period of the structure 40 to which the point -to-point radio
antenna 10 is attached is considered to be in a range of about 0.05 second to about
10 seconds, and typically in a range of about 0.1 second to about 1 second.
15 [0028]
Fig. 3 is a frequency distribution diagram showing one example of
influence of mechanical vibrations of the antenna 10 or 20 on the communication
qual ity. The communication qual ity i s, for example, received signal strength, an
SNR, or a BER. The graph shown by the dashed line in Fig. 3 indicates
20 distribution of the communicat ion quality of the radio link 50 when neither
mechanical vibrations of the antennas 10 nor 20 occur. In contrast , the graph
shown by the solid line in Fig. 3 indicates distribution of the communication
qual ity of the radio l ink 50 when mechanical vibrations of the antennas 10 and 20
occur. It should be noted that, when the mechanical vibrations occur, the average
25 value (or median value) of the communication quality decreases and, furthermore,
the fluctuat ion (variation) of the communication quality increases. As described
above, the time scale of the fluctuations in the communication qual ity is
determined by the natural period of the structure 40, to which the antenna 10 or 20
is at tached, and is much shorter than the t ime scale of changes in the
30 meteorological condi tions (e.g., rain, fog, mist, haze, smoke, or smog).
[0029]
As can be understood from the above description, the "average value" of
the communication quality, which is used in the AMC as an index to deal with
changes in the propagation state due to meteorological conditions , may be
10
unsuitable to be used as an index to observe degradation of the communication
qual ity due to mechanical vibrat ions of the antenna 10 or 20. This is because the
"average value" of the communication quality cannot sufficient ly express the
fluctuation (variation) of the communication qual ity due to mechanical vibrat ions.
5 [0030]
Further, in the observation of the communication quality with a long t ime
scale (e.g., observation at intervals of from one minute to one hour ) for the AMC
to deal wi th changes in the propagation state due to the meteorological conditions ,
degradation of the communicat ion quality due to mechanical vibrations of the
10 antenna 10 or 20 could not be observed. This is because the time scale of the
vibration period of the antenna 10 or 20, which is determined according to the
natural period of the structure 40, is much shorter than the time scale of the speed
of changes in weather .
[0031]
15 In view of the aforementioned discussion, each of the controllers 12 and
22 is configured to adjust a modulat ion scheme, a code rate and the like based on
mechanical vibrations of the antenna 10 or 20. Specifically, in some
implementations, each of the controllers 12 and 22 adjust s at least one of the
following (a) to (e) in response to detection of mechanical vibrat ions of the
20 antenna 10 or 20 (or according to the magnitude of the mechanical vibrations):
(a) modulation scheme appl ied to a transmission signal of the transceiver 11 (or
21);
(b) code rate applied to a transmission signal of the transceiver 11 (or 21);
(c) transmission power applied to a transmission signal of the transcei ver 11 (or
25 21);
(d) transmission beam width applied to a transmission signal of the transceiver 11
(or 21); and
(e) reception beam width applied to a rece ived signal of the transceiver 11 (or 21).
[0032]
30 For example, when mechanical vibrations of the ant enna 10 or 20 are
detected, the controller 12 may change the modulation scheme to be appl ied to the
transmission signal of the transceiver 11 from a first modulation scheme having a
small inter -symbol distance (e.g. , 64 quadrature amplitude modulation (64-QAM))
to a second modulation scheme having a large inter-symbol distance (e.g.,
11
16-QAM or quadrature phase shift keying (QPSK)). Further or alternatively, the
control ler 12 may select one of modulation schemes so that the inter -symbol
distance becomes larger as the mechanical vibrat ions of the antenna 10 or 20
become larger. The mechanical vibrations of the antenna 10 or 20 may increase a
propagat ion loss of the radio link 50 and decrease the received 5 signal strength.
Accordingly, while the mechanical vibrations of the antenna 10 or 20 are
occurring, using the modulation scheme having a relatively large inter-symbol
distance, which is more tolerant to noise and interference, can suppress increase in
the code error rate.
10 [0033]
When mechanical vibrat ions of the antenna 10 or 20 are detected, the
control ler 12 may decrease the code rate to be applied to the transmission signal of
the transceiver 11 (that is, increase the redundancy of the transmission signal) .
Further or alternatively, the controller 12 may decrease the code rate as the
15 mechanical vibrations of the antenna 10 or 20 increase. It is thus possible to
suppress increase in the code error rate due to the mechanical vibrations of the
antenna 10 or 20.
[0034]
When mechanical vibrat ions of the antenna 10 or 20 are detected, the
20 control ler 12 may increase the transmission power of the transceiver 11. Further
or alternatively, the controller 12 may increase the transmission power of the
transceiver 11 as the mechanical vibrations of the antenna 10 or 20 increase. It is
thus possible to compensate for decrease in the received signal strength due to the
mechanical vibrations of the antenna 10 or 20, whereby it is possible to suppress
25 increase in the code error rate.
[0035]
When mechanical vibrat ions of the antenna 10 or 20 are detected, the
control ler 12 may increase one or both of the transmission beam width and the
reception beam width of the antenna 10. Further or alternatively, the controller
30 12 may increase one or both of the transmission beam width and the reception
beam width as the mechanical vibrations of the antenna 10 or 20 increase. When
a narrow directed beam is used while the mechanical vibrations of the antenna 10
or 20 are occurring, a range of fluctuations in the received signal strength becomes
wide. Therefore, by using relatively wide directed beam while the mechanical
12
vibrations of the antenna 10 or 20 are occurring, the range of fluctuation s in the
received signal strength can be made narrow, and the range of fluctuations in the
code error rate can be reduced.
[0036]
In one example, mechanical vibrat ions of the antenna 10 5 or 20 are directly
detected using a vibration sensor . The vibration sensor measures displacement ,
velocity, or accelerat ion of an object . In some implementations, the vibrat ion
sensor is coupled to the structure 40, the antenna 10 (20), or the transceiver 11
(21) and measures displacement , velocity, or acceleration of the structure 40, the
10 antenna 10 (20), or the transceiver 11 (21). By using the vibration sensor , it is
possible to directly observe the mechanical vibrations of the structure 40, the
antenna 10 (20), or the transceiver 11 (21).
[0037]
In another example, mechanical vibrations of the antenna 10 or 20 are
15 indirectly detected by observing fluctuations in the communication quali ty of the
radio l ink 50. For example, each of the controllers 12 and 22 may indirect ly
detect the mechanical vibrat ions using a quality index indicating a magnitude of
fluctuations in the communicat ion quality of the radio link 50. Specifically, each
of the controllers 12 and 22 may determine that the mechanical vibrat ions are
20 occurring in the antenna 10 or 20 in response to detecting that the magnitude of
fluctuations in the communicat ion quality of the radio link 50 exceeds a
predetermined level (threshold). This method of using the communication quality
of the radio link 50 has the advantages that there is no need to use a vibration
sensor and there is no need to provide a new interface to supply the output signa l
25 of the vibration sensor to the controllers 12 and 22. Another advantage of using
the communication quality of the radio link 50 is that it is highly compatible with
an existing AMC that also uses the communication qual ity of the radio link 50,
which means that this method can be easily implemented by an improvement of the
existing AMC algorithm.
30 [0038]
The quality index indicating a magnitude of fluctuations in the
communicat ion quality may be a statistical value (e.g., a standard deviation or
dispersion) which indicates a magnitude of variation among measurement values of
the communication quality. The measurement values of the communicat ion
13
qual ity are preferably measured repeatedly at a time interval shorter than the
natural period of the structure 40 or the forced vibration period of the structure 40
due to wind, so that the mechanical vibrations can be detected. The natural
period of the structure 40 or the forced vibrat ion period of the structure 40 due to
wind is in a range of about 0.05 second to 10 seconds, and is typically 5 in a range of
about 0.1 second to 1 second.
[0039]
Fig. 4 is a flowchart showing one example of the adaptive control
procedure performed by the controllers 12 and 22. In Step S11, the controller 12
10 (22) acquires a magni tude of mechanical vibrations of the antenna 10 or 20 that
have been directly or indirectly detected. The magnitude of the mechanical
vibrations may be calculated using an output signal of a vibration sensor or using
measurement values of the communication quality of the radio link 50. In Step
S12, the controller 12 (22) adjusts at least one of a modulation scheme, a code rate,
15 transmission power , transmission beam width, and reception beam width,
according to the magnitude of the mechanical vibrations of the antenna 10 or 20.
[0040]
As stated above, the point -to-point radio system according to this
embodiment is configured to adjust at least one of a modulation scheme, a code
20 rate, transmission power , and transmission beam width, based on mechanical
vibrations of the antenna 10 or 20. Accordingly, the point -to-point radio system
according to this embodiment can suppress degradation of the communication
qual ity of the point -to-point radio link 50 due to the mechanical vibrations of the
structure 40 to which the communication apparatus 1 or 2 (antenna 10 or 20) is
25 attached.
[0041]
Second embodiment
In this embodiment , one specific example of configurations of the
point -to-point radio system and the adaptive control procedures described in the
30 first embodiment will be described. In this embodiment , an example in which a
modulation scheme, a code rate and the like are adjusted according to a magnitude
of fluctuations in communicat ion quality of the radio link 50 calculated from a
plurality of measurement values of the communicat ion quality is described. The
configuration example of the point -to-point radio system according to this
14
embodiment is similar to that of Fig. 1.
[0042]
Fig. 5 is a block diagram showing a configuration example of the
communicat ion apparatus 1 according to this embodiment . The communication
apparatus 2 has a similar configuration as the communication 5 apparatus 1. The
communicat ion apparatus 1 shown in Fig. 5 includes an antenna 10, a controller
12, a transmi tter 13, a receiver 14, and a duplexer 15. The transmitter 13 and the
receiver 14 correspond to the transceiver 11 shown in Fig. 1. Fig. 5 shows an
example in which bidirectional communication is performed by frequency division
10 duplex (FDD) and accordingly the duplexer 15 is used to separate a transmission
frequency band from a reception frequency band. However, the communication
apparatus 1 may perform bidirectional communicat ion by time division duplex
(TDD). In the case of the TDD, a high-frequency switch may be used in place of
the duplexer 15 to switch transmission and recept ion.
15 [0043]
The transmitter 13 shown in Fig. 5 includes a forward error correction
(FEC) encoder 131, a modulator 132, a DA converter 133, and a TX-RF 134. The
FEC encoder 131 performs channel coding on transmission data using a FEC
scheme. The modulator 132 receives a coded data sequence generated by the FEC
20 encoder 131, maps the coded data sequence to transmission symbols, limits the
band of the transmission symbol sequence using a low-pass filter, and thus
generates a transmission baseband signal . The DA converter 133 converts the
digital transmission baseband signal into an analog signal . The TX-RF 134
generates a modulated signal by mixing the analog transmission baseband signal
25 with a local oscillator signal , up-converts the modulated signal to a carrier
frequency (radio frequency (RF)), and amplifies the RF signal and sends it to the
antenna 10.
[0044]
The receiver shown in Fig. 5 includes an RX-RF 141, an AD converter
30 142, a demodulator 143, and an FEC decoder 144. The RX-RF 141 amplifies a
received RF signal , received by the antenna 10, with a Low Noise Amplifier (LNA)
and down-converts the received RF signal to an intermediate frequency (IF) band.
The AD converter 142 converts the received IF signal into a digi tal signal . The
demodulator 143 performs demodulation processing in the digital domain. That
15
is, the demodulator 143 mul tiplies the digi tal received IF signal with a digital
sinusoidal signal , performs low-pass fil ter processing, and thus generates a
quadrature baseband signal . Further, the demodulator 143 performs symbol
determination (symbol demapping) of the quadrature baseband signal to generate a
received data sequence. The FEC decoder 144 carries out error 5 correction of the
received data sequence in accordance with the channel coding scheme executed in
the opposing apparatus (communication apparatus 2).
[0045]
The controller 12 refers to communicat ion qual ity obtained by the receiver
10 14 and adaptively adjusts at least one of the modulation scheme in the modulator
132, the code rate in the FEC encoder 131, the transmission power in the TX-RF
134, and the transmission beam width (transmission weight vector) in the TX-RF
134. The controller 12 may adapt ively adjust the reception beam width (reception
weight vector) in the RX-RF 141. The communicat ion quality obtained by the
15 receiver 14 is, for example, received signal strength (RSSI) obtained in the RX-RF
141, an SNR obtained in the demodulator 143, or a BER obtained in the FEC
decoder 144.
[0046]
Further, the controller 12 according to this embodiment observes
20 fluctuations in communication quality of the radio link 50 and adjusts the
modulation scheme, the code rate and the l ike based on the magnitude of
fluctuations in the communicat ion quality. That is, the control ler 12 according to
this embodiment indirectly detects mechanical vibrations of the antenna 10 by
observing fluctuations in the communication qual ity of the radio link 50 .
25 [0047]
Fig. 6 is a flowchart showing one example of the adaptive control
procedure performed by the controller 12 according to this embodiment . The
control ler 22 performs an adaptive control procedure similar to that in the
control ler 12. In Step S21, in order to detect fluctuations in the communication
30 qual ity of the radio link 50 occurring probably due to mechanical vibrations of the
antenna 10, the controller 12 acquires a plurality of measurement values of
communicat ion quality repeatedly measured at a time interval shorter than the
natural period (or the forced vibration period due to wind) of the structure 40 to
which the antenna 10 is attached. As already stated above, the natural period of
16
the structure 40 or the forced vibration period due to wind of the structure 40 is in
a range of about 0.05 second to about 10 seconds and is typical ly in a range of
about 0.1 second to about 1 second. The control ler 12 then calculates a statistical
value (e.g., a standard deviation or dispersion) indicating a magnitude of
variations among the plurality of measurement values of 5 the communicat ion
qual ity.
[0048]
In Step S22, the controller 12 adjusts at least one of the modulation
scheme, the code rate, the transmission power , the transmission beam width, and
10 the reception beam width according to the magnitude of fluctuat ions in the
communicat ion quality of the radio link 50.
[0049]
Third embodiment
In this embodiment , another specific example of configurations of the
15 point -to-point radio system and the adaptive control procedure s described in the
first embodiment will be described. In this embodiment , an example in which a
modulation scheme, a code rate and the like are adjusted according to a magnitude
of mechanical vibrations which have been directly detected by a vibrat ion sensor
will be described. The configurat ion example of the point -to-point radio system
20 according to this embodiment is simi lar to that of Fig. 1.
[0050]
Fig. 7 is a block diagram showing a configuration example of the
communicat ion apparatus 1 according to this embodiment . The communication
apparatus 2 has a similar configuration as the communication apparatus 1. The
25 communicat ion apparatus 1 shown in Fig. 7 includes a vibration sensor 31. The
vibration sensor 31 is coupled to the structure 40, the communicat ion apparatus 1,
or the antenna 10 and measures displacement, velocity, or acceleration of the
structure 40, the communication apparatus 1, or the antenna 10. The controller
12 according to this embodiment receives an output signal of the vibration sensor
30 31 and detects mechanical vibrat ions of the antenna 10 (or the structure 40) based
on the output signal of the vibration sensor 31. Since the configurations and the
operations of the other elements shown in Fig. 7 are similar to those of the
elements denoted by the same reference symbols in Fig. 5, the descriptions thereof
will be omitted.
17
[0051]
Fig. 8 is a flowchart showing one example of the adaptive control
procedure performed by the controller 12 according to this embodiment . The
control ler 22 performs an adaptive control procedure similar to that in the
control ler 12. In Step S31, the control ler 12 detects mechanical 5 vibrations of the
antenna 10 (or the structure 40) based on the output signal of the vibration sensor
31. In Step S32, the controller 12 adjusts at least one of the modulation scheme,
the code rate, the transmission power , the transmission beam width, and the
reception beam width according to a magni tude of the mechanical vibrations of the
10 antenna 10 (or the structure 40).
[0052]
Fourth embodiment
In this embodiment , an improvement of the second embodiment will be
described. The configuration example of the point -to-point radio system
15 according to this embodiment is simi lar to that of Fig. 1. In this embodiment ,
each of the communication apparatuses 1 and 2 (control lers 12 and 22) performs
both first adaptive processing to deal with fluctuation s in the communication
qual ity of the radio l ink 50 due to mechanical vibrations of the antenna 10 and
second adaptive processing to deal with degradat ion of the communicat ion quality
20 of the radio link 50 due to meteorological conditions (e.g. , rain, fog, mist, haze,
smoke, or smog) . In the following description, the first adapt ive processing and
the second adaptive processing are respectively called a first AMC and a second
AMC.
[0053]
25 The first AMC is similar to adaptive processing described in the first and
second embodiments . That is, in the first AMC, each of the control lers 12 and 22
calculates a magnitude of fluctuations in the communication quality (e.g., RSSI,
SNR, or BER) of the radio l ink 50 using a plurality of measurement values of the
communicat ion quality repeatedly measured at an interval shorter than the natural
30 period (or the forced vibration period due to wind) of the structure 40 and adjusts
the modulat ion scheme, the code rate and the like according to the magnitude of
fluctuations in the communicat ion quality.
[0054]
Meanwhile, the second AMC is an AMC to deal with changes in the
18
propagat ion state due to meteorological conditions. That is, in the second AMC,
each of the controllers 12 and 22 adjusts the modulation scheme, the code rate and
the like according to a magnitude of an average of measurement values of the
communicat ion quality of the radio link (e.g., RSSI, SNR, or BER) observed wi th a
long t ime scale corresponding to speed of changes in weather 5 (e.g., observed at
intervals of from one minute to one hour ). The reason for using the average value
of the communication quality is to avoid following sudden short-time fluctuations
in the communication quality.
[0055]
10 As can be understood from the above description, the first and second
AMCs should use different communication quality indices with different time
scales. The first AMC uses a statistical value (e.g., a standard deviation or
dispersion) indicat ing a magnitude of fluctuations in the communication quality of
the radio link 50 in a period shorter than the natural period of the structure 40, in
15 order to determine the mechanical vibrations of the antenna 10. On the other
hand, the second AMC uses an average value of the communicat ion quality of the
radio l ink 50, in order to determine degradation of line-of-sight visibility between
the antennas 10 and 20 due to changes in weather in a relat ively long t ime scale
and in order to avoid following sudden short -t ime fluctuations in the qual ity of the
20 radio l ink.
[0056]
Fig. 9 is a flowchart showing one example of the adaptive control
procedure performed by the controller 12 according to this embodiment . The
control ler 22 performs an adaptive control procedure similar to that in the
25 control ler 12. In the example shown in Fig. 9, a standard deviation of the
communicat ion quality is used to indicate a magnitude of fluctuations in the
communicat ion quality of the radio link 50. In the example shown in Fig. 9, the
first AMC (S41), to deal wi th the mechanical vibrations of the antenna 10, is
preferentially performed. If it is determined that the fluctuations in the
30 communicat ion quality due to the mechanical vibrations of the antenna 10 are
small , then the second AMC (S45), to deal with changes in the meteorological
conditions, is performed.
[0057]
The first AMC (S41) shown in Fig. 9 includes Steps S42 to S44. In Step
19
S42, the controller 12 calculates the s tandard deviation of the communication
qual ity of the radio link 50. As already stated above, this standard deviation may
be a standard deviation of the plurality of measurement values of the
communicat ion quality repeatedly measured during a time period that is shorter
than the natural period of the structure 40. In Step S43, 5 the control ler 12
determines whether the standard deviation of the communication quality exceeds a
predetermined threshold. When the standard deviation of the communication
qual ity exceeds the threshold (YES in Step S43), the control ler 12 carries out the
AMC based on the standard deviation of the communication quality (Step S44).
10 For example, the controller 12 adjust s at least one of the modulation scheme, the
code rate, the transmission power, the transmission beam width, and the reception
beam width according to the magnitude of the standard deviation of the
communicat ion quality.
[0058]
15 On the other hand, when the standard deviation of the communication
qual ity is equal to or smaller than the predetermined threshold (NO in Step S43),
the controller 12 performs the second AMC (S45). That is, the controller 12
calculates an average value of the communication quality of the radio link 50 (Step
S46) and performs AMC based on the average value of the communication quality
20 (Step S47). For example, the controller 12 adjust s at least one of the modulation
scheme, the code rate, the transmission power , the transmission beam width, and
the reception beam width according to the magnitude of the average value of the
communicat ion quality.
[0059]
25 As will be understood from the above description, the point-to-point radio
system according to this embodiment performs both the first AMC to address the
mechanical vibrations of the antenna 10 and the second AMC to address
degradation of line-of-sight visibility between the antennas 10 and 20 due to
changes in weather , whereby it is possible to keep the communication qual ity of
30 the radio link 50 more rel iably.
[0060]
Other embodiments
The adaptive control described in the plurality of embodiments stated
above may be performed only in the communication apparatus 1 or 2. For
20
example, such an adaptive control may be performed only in the communication
apparatus 1 or 2 that is attached to the st ructure (a lamp post , a bus shelter and the
like) that tends to be easily deformed by an external force.
[0061]
In the plurality of embodiments stated above, the examples 5 in which the
communicat ion apparatuses 1 and 2 bidirectionally transmit signals vi a the
point -to-point radio l ink have been described. However, the communication
apparatuses 1 and 2 may be configured to transmit signals only in one direction via
the point-to-point radio link. In this case, the communication qual ity (received
10 signal quality) measured in the receiving communication apparatus (e.g. ,
communicat ion apparatus 2) may be fed back to the transmitting communication
apparatus (e.g., communication apparatus 1) . This feedback may be performed
via a control line different from the point -to-point radio link.
[0062]
15 The architectures of the communication apparatuses 1 and 2 shown in Figs.
5 and 7 are merely examples. Various types of transmission and reception
archi tecture for point -to-point radio have been proposed. The communication
apparatuses 1 and 2 may employ these various types of transmission and recept ion
archi tecture.
20 [0063]
The plurality of embodiments stated above may be combined as
appropriate.
[0064]
The adaptive processing performed by each of the controllers 12 and 22
25 described in the plurality of embodiments stated above may be implemented using
a semiconductor processing device including an Application Specific Integrated
Circuit (ASIC). Further, these processing may be implemented by causing a
computer system including at least one processor (e.g. , microprocessor or Digital
Signal Processor (DSP)) to execute a program. Specifically, one or more
30 programs including instruct ions to cause a computer system to perform the
algorithms described with reference to the flowcharts and the like may be created
and these programs may be supplied to the computer system.
[0065]
The program(s) can be stored and provided to a computer using any type of
21
non-transitory computer readable media. Non-transitory computer readable
media include any type of tangible storage media. Examples of non -transitory
computer readable media include magnetic storage media (such as flexible disks,
magnetic tapes, hard disk drives, etc.), opt ical magnetic storage media (e.g.,
magneto-optical disks), Compact Disc Read Only Memory 5 (CD-ROM), CD-R,
CD-R/W, and semiconductor memories (such as mask ROM, Programmable ROM
(PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM),
etc.). The program(s) may be provided to a computer using any type of transitory
computer readable media. Examples of transitory computer readable media
10 include electric signals, optical signals, and electromagnetic waves. Transitory
computer readable media can provide the program(s) to a computer via a wired
communicat ion line (e.g., electric wires, and optical fibers) or a wireless
communicat ion line.
[0066]
15 The above embodiments are merely examples of applications of technical
ideas obtained by the present inventor. Needless to say, these technical ideas ar e
not limi ted to the above embodiments and various modifications can be performed
on these technical ideas.
[0067]
20 For example, the whole or part of the embodiments disclosed above can be
described as, but not limited to, the fol lowing supplementary not es.
[0068]
(Supplementary Note 1)
A point -to-point radio system, including:
25 first and second communication apparatuses configured to be respectively
connected to first and second antennas and to perform communication through the
first and second antennas, the first and second antennas being respectively
attached to first and second structures; and
a control unit that adjusts , based on a qual ity index related to mechanical
30 vibrations of at least one of the first and second structures, a radio communicat ion
parameter to be appl ied to the communicat ion.
[0069]
(Supplementary Note 2)
The point -to-point radio system according to Supplementary Note 1, in
22
which the radio communication parameter includes at least one of a modulation
scheme, a code rate, transmission power, transmission beam width, and reception
beam width.
[0070]
(Supplementary 5 Note 3)
The point -to-point radio system according to Supplementary Note 1 or 2,
in which the quality index indicates a magnitude of variations among
communicat ion quality measurement values repeatedly measured at a time interval
that is shorter than a natural period of the first or second structure or than a forced
10 vibration period due to wind of the first or second structure.
[0071]
(Supplementary Note 4)
The point-to-point radio system according to Supplementary Note 3, in
which each of the natural period and the forced vibration period is in a range of
15 0.05 to 10 seconds.
[0072]
(Supplementary Note 5)
The point -to-point radio system according to Supplementary Note 1 or 2,
in which the quality index is a standard deviation or dispersion of a plural ity of
20 communicat ion quality measurement values repeatedly measured at a time interval
that is shorter than a predetermined period of time .
[0073]
(Supplementary Note 6)
The point -to-point radio system according to Supplementary Note 5, in
25 which the predetermined period of time is in a range of 0.05 to 10 seconds .
[0074]
(Supplementary Note 7)
The point -to-point radio system according to any one of Supplementary
Notes 1 to 6, in which the control unit increases transmission beam width or
30 reception beam width of the first or second antenna as the mechanical vibrations
increase.
[0075]
(Supplementary Note 8)
A point -to-point radio system, including:
23
first and second communication apparatuses configured to be respectively
connected to first and second antennas and to perform communication through the
first and second antennas, the first and second antennas being respectively
attached to first and second structures ; and
a control unit that adjusts , based on a first quality 5 index related to
propagat ion characteristics of a radio link and a second quality index related to
mechanical vibrations of at least one of the first and second structures, a radio
communicat ion parameter to be applied to the communication .
[0076]
10 (Supplementary Note 9)
The point -to-point radio system according to Supplementary Note 8, in
which the radio communication parameter includes at least one of a modulation
scheme, a code rate, transmis sion power, transmission beam width, and reception
beam width.
15 [0077]
(Supplementary Note 10)
The point -to-point radio system according to Supplementary Note 8 or 9,
in which
the first quality index indicates communication quality regarding the
20 communicat ion per first time period, and
the second quality index indicates a magni tude of fluctuations in
communicat ion quality of the radio link derived from a plurali ty of communication
qual ity measurement values repeatedly measured during a second time period that
is shorter than the first time period.
25 [0078]
(Supplementary Note 11)
The point -to-point radio system according to any one of Supplementary
Notes 8 to 10, in which the second quality index indicates a magnitude of
fluctuations in communication quality of the radio link occurring due to the
30 mechanical vibrations of the first or second structure.
[0079]
(Supplementary Note 12)
The point -to-point radio system according to any one of Supplementary
Notes 8 to 11, in which the second time period is determined according to a natural
24
period of the first or second structure or a forced vibration period due to wind of
the first or second structure.
[0080]
(Supplementary Note 13)
The point -to-point radio system according to any one 5 of Supplementary
Notes 8 to 12, in which the second quality index is a standard deviation or
dispersion of a plural ity of communication quality measurement values regarding
the communication.
[0081]
10 (Supplementary Note 14)
The point -to-point radio system according to Supplementary Note 10, in
which the second time period is in a range of 0.05 to 10 seconds .
[0082]
(Supplementary Note 15)
15 The point -to-point radio system according to any one of Supplementary
Notes 8 to 14, in which the first quality index indicates degradat ion of the
communicat ion quality of the radio link occurring due to degradation of
line-of-sight visibility between the first antenna and the second antenna according
to meteorological conditions.
20 [0083]
(Supplementary Note 16)
The point -to-point radio system according to any one of Supplementary
Notes 8 to 15, in which the first quality index indicates degradation of the
communicat ion quality of the radio link caused by an attenuation effect of at least
25 one of rain, fog, mist , haze, smoke, and smog.
[0084]
(Supplementary Note 17)
The point -to-point radio system according to any one of Supplementary
Notes 8 to 16, in which the first quality index is an average value of
30 communicat ion quality of the radio link.
[0085]
(Supplementary Note 18)
The point -to-point radio system according to Supplementary Note 10 or
14, in which the first time period is in a range of one minute to one hour .
25
[0086]
This applicat ion is based upon and claims the benefit of priority from
Japanese Patent Appl ication No. 2013-149366, filed on July 18, 2013, the
disclosure of which is incorporated herein in its entirety by reference.
Reference 5 Signs List
[0087]
1, 2 COMMUNICATION APPARATUS
10, 20 ANTENNA
11, 21 TRANSCEIVER
10 12, 22 CONTROLLER
13 TRANSMITTER
14 RECEIVER
15 DUPLEXER
31 VIBRATION SENSOR
15 40 STRUCTURE
50 POINT-TO-POINT RADIO LINK
51 DIRECTED BEAM
131 FORWARD ERROR CORRECTION (FEC) ENCODER
132 SYMBOL MAPPER
20 133 DA CONVERTER
134 TRANSMISSION RF UNIT (TX-RF)
141 RECEPTION RF UNIT (RX-RF)
142 AD CONVERTER
143 DEMODULATOR
25 144 FEC DECODER

WE CLAIM:
1. A point -to-point radio system, comprising:
first and second communication apparatuses configured to be respectively
connected to first and second antennas and to perform communication 5 through the
first and second antennas, the first and second antennas being respectively
attached to first and second structures; and
control means for adjust ing, based on a quality index related to mechanical
vibrations of at least one of the first and second structures, a radio communication
parameter to be appl ied to the communicat ion.
2. The point -to-point radio system according to Claim 1, wherein the
radio communication parameter comprises at least one of a modulation scheme, a
code rate, transmission power, transmission beam width, and reception beam
width.
3. The point -to-point radio system according to Claim 1 or 2, further
comprising detection means for directly or indirectly detect ing the mechanical
vibration,
20 wherein the quality index is calculated based on a detection result by the
detection means.
4. The point -to-point radio system according to Claim 3, wherein the
detection means directly measures the mechanical vibrations using a vibrat ion
sensor coupled to the first antenna, the second antenna, the f irst structure, or the
second structure.
5. The point -to-point radio system according to Claim 3, wherein the
detection means indirectly measures the mechanical vibrations based on
fluctuations in communication quality regarding the communication .
6. A communication apparatus comprising:
an antenna attached to a structure;
communicat ion means electrically connected to the antenna; and
control means for control ling, based on a qual ity index indicating
communicat ion quality related to vibrations of the structure, a radio
communicat ion parameter to be applied to the communication means.
7. The communication apparatus according to Claim 6, 5 wherein the radio
communicat ion parameter comprises at least one of a modulation scheme, a code
rate, transmission power, transmission beam width, and reception beam width .
8. The communication apparatus according to Claim 6 or 7, further
comprising detection means for directly or indirectly detect ing the vibration,
wherein the quality index is calculat ed based on a detection result by the
detection means.
9. The communication apparatus according to Claim 8, wherein the
detection means directly measures the vibrat ions using a vibrat ion sensor coupled
to the antenna or the structure.
10. The communication apparatus according to Claim 8, wherein the
detection means indirectly measures the mechanical vibrations based on
fluctuations in communication quality regarding the communication .
11. A communication control method for a point -to-point radio
communicat ion, the method comprising:
performing communication through an antenna attached to a structure; and
control ling, based on mechanical vibrations of the structure, a radio
communicat ion parameter to be applied to the communication.
12. A non-transitory computer readable medium storing a program for
causing a computer to perform a communication control method for a
30 point -to-point radio communication through an antenna attached to a structure,
wherein the communication control method includes adjusting, based on
mechanical vibrations of the structure, a radio communication parameter to be
appl ied to the communication.
13. A point -to-point radio system, comprising:
first and second communication apparatuses configured to be respectiv ely
connected to first and second antennas and to perform communication through the
first and second antennas, the first and second antennas being respectively
attached to first and second 5 structures; and
control means for adjusting, based on a first qual ity index related to
propagat ion characteristics of a radio link and a second quality index related to
mechanical vibrations of at least one of the first and second structures, a radio
communicat ion parameter to be applied to the communication .
14. The point-to-point radio system according to Claim 13, wherein the
radio communication parameter comprises at least one of a modulation scheme, a
code rate, transmission power, transmission beam width, and reception beam
width.
15. The point -to-point radio system according to Claim 13 or 14, further
comprising detection means for directly or indirectly detect ing the mechanical
vibration,
wherein the second quality index is calculated based on a detection result
by the detection means.
16. The point-to-point radio system according to Claim 15, wherein the
detection means directly measures the mechanical vibrations using a vibrat ion
sensor coupled to the first antenna, the second antenna, the first structure, or the
second structure.
17. The point-to-point radio system according to Claim 15, wherein the
detection means indirectly measures the mechanical vibrations based on
fluctuations in communication quality regarding the communication .
18. A communication apparatus that performs a point -to-point radio
communicat ion, the communication apparatus comprising:
communicat ion means connected to an antenna attached to a structure; and
control means for adjusting, based on a first quality index related to
propagat ion characteristics of a radio link and a second quality index related to
mechanical vibrations of the structure, a radio communication parameter to be
appl ied to the communication.
19. The communication apparatus according to Claim 5 18, wherein the
radio communication parameter comprises at least one of a modulation scheme, a
code rate, transmission power, transmission beam width, and reception beam
width.
20. A communication control method for a point -to-point radio
communicat ion, the method comprising:
performing communication through an antenna attached to a structure; and
adjusting, based on a first quality index related to propagat ion
characteristics of a radio link and a second index related to mechanical vibrat ions
of the structure, a radio communication parameter to be appl ied to the
communicat ion.
21. A non-transitory computer readable medium that stores a program for
causing a computer to perform a communication control method for a
point -to-point radio communication through an antenna attached to a structure,
wherein the communication control method includes adjusting, based on a
first qual ity index related to propagation characteristics of a radio link and a
second index related to mechanical vibrations of the structure, a radio
communicat ion parameter to be applied to the communication.