U.S. patent application number 11/758088 was filed with the patent office on 2008-02-07 for radio access point testing apparatus.
Invention is credited to Kiyoshi Kawamoto, Akihiko Yoshida.
Application Number | 20080031144 11/758088 |
Document ID | / |
Family ID | 38929974 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080031144 |
Kind Code |
A1 |
Kawamoto; Kiyoshi ; et
al. |
February 7, 2008 |
RADIO ACCESS POINT TESTING APPARATUS
Abstract
In a case where reception power in a radio access point is high
by external noise, the normalcy of the radio access point is
tested. In order to judge the normalcy of the radio characteristic
of the radio access point, a test is performed through the calling
connection between a testing access terminal in the radio access
point and a predetermined device. An RSSI is measured before and
after the transmission of a test signal. When the RSSI exceeds a
threshold value, the path loss of a reverse link connected from the
radio access point to the testing access terminal is increased by
an attenuator. Then, reception power in the testing access terminal
decreases. Thus, initial transmission power in accordance with the
reception power from the testing access terminal is raised and the
calling connection of the testing access terminal can be performed
even under the external noise.
Inventors: |
Kawamoto; Kiyoshi;
(Yokohama, JP) ; Yoshida; Akihiko; (Yokohama,
JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET
SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
38929974 |
Appl. No.: |
11/758088 |
Filed: |
June 5, 2007 |
Current U.S.
Class: |
370/242 ;
455/67.13 |
Current CPC
Class: |
H04W 52/245 20130101;
H04W 24/06 20130101; H04W 52/243 20130101; H04W 52/20 20130101;
H04W 52/50 20130101; H04W 52/24 20130101; H04W 88/08 20130101; H04W
76/10 20180201 |
Class at
Publication: |
370/242 ;
455/067.13 |
International
Class: |
H04L 12/26 20060101
H04L012/26; H04B 17/00 20060101 H04B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2006 |
JP |
2006-160862 |
Claims
1. A radio access point testing apparatus, comprising: a terminal
function portion which has a transmission function and a reception
function of a communication terminal in a radio communication
system, and an initial transmission power from the terminal
function portion in case of performing a calling connection is
determined in accordance with reception power; a radio processing
unit which includes a transmitter for transmitting signals to said
terminal function portion and the communication terminal, a
receiver for receiving signals from said terminal function portion
and the communication terminal, and a measurement part for
measuring reception power in said receiver as includes power of the
radio signal from the communication terminal and/or interference
waves; an attenuator which adjusts a path loss between said
transmitter and said terminal function portion; and a control unit
which performs the calling connection between said terminal
function portion and a predetermined device, through said radio
processing unit, so as to test normalcy and abnormalcy of a radio
access point; wherein said attenuator increases the path loss in
accordance with a value of the reception power measured in said
measurement part, thereby to decrease the reception power in said
terminal function portion and to consequently increase the initial
transmission power; said terminal function portion performs the
calling connection with the predetermined device by the increased
initial transmission power; and said control unit performs the test
of the radio access point.
2. A radio access point testing apparatus, comprising: a terminal
function portion which has a transmission function and a reception
function of a communication terminal in a radio communication
system, and an initial transmission power in case of performing a
calling connection is previously set; a radio processing unit which
includes a transmitter for transmitting signals to said terminal
function portion and the communication terminal, a receiver for
receiving signals from said terminal function portion and the
communication terminal, and a measurement part for measuring
reception power in said receiver as includes power of the radio
signal from the communication terminal and/or interference waves;
and a control unit which performs the calling connection between
said terminal function portion and a predetermined device, through
said radio processing unit, so as to test normalcy and abnormalcy
of a radio access point; wherein said terminal function portion
increases the set initial transmission power in accordance with a
value of the reception power measured by said measurement part;
said terminal function portion performs the calling connection with
the predetermined device by the increased initial transmission
power; and said control unit performs the test of the radio access
point.
3. A radio access point testing apparatus as defined in claim 1,
wherein said control unit evaluates a difference between the value
of the reception power measured by said measurement part and the
transmission power of said terminal function portion adjusted so as
to satisfy a desired packet error rate in said radio processing
unit, and compares the evaluated difference and a predetermined
threshold value, thereby to judge the normalcy and abnormalcy of
the radio access point.
4. A radio access point testing apparatus as defined in claim 3,
wherein said control unit evaluates the difference by using a value
obtained by converting the transmission power into power of an
antenna end of the radio access point.
5. A radio access point testing apparatus as defined in claim 3,
wherein said control unit judges that the radio access point is
normal, in a case where the evaluated difference is smaller than
the predetermined threshold value, and judges that the radio access
point is abnormal, in a case where the evaluated difference is not
smaller than the predetermined threshold value.
6. A radio access point testing apparatus as defined in claim 1,
further comprising: a noise generation portion which generates
noise; and a combiner which generates a test signal by superposing
the noise from said noise generation portion, on a signal outputted
from said terminal function portion, and which outputs the test
signal to said radio processing unit; wherein said terminal
function portion adjusts the transmission power so as to satisfy a
desired packet error rate or signal-to-noise ratio; and the
transmission power from said terminal function portion is set at
power which is higher than the reception power measured by said
measurement part or external noise, by superposing the noise.
7. A radio access point testing apparatus as defined in claim 6,
wherein: a signal quality of the test signal is set at a value
which is required for satisfying the desired packet error rate and
which has a small margin; and a packet error rate of the test
signal is measured, and the normalcy and abnormalcy of the radio
access point is judged depending upon whether or not the measured
packet error rate satisfies the desired packet error rate.
8. A radio access point testing apparatus as defined in claim 6,
further comprising a second attenuator which adjusts a magnitude of
the noise component from said noise generation portion.
9. A radio access point testing apparatus as defined in claim 2,
wherein said control unit evaluates a difference between the value
of the reception power measured by said measurement part and the
transmission power of said terminal function portion adjusted so as
to satisfy a desired packet error rate in said radio processing
unit, and compares the evaluated difference and a predetermined
threshold value, thereby to judge the normalcy and abnormalcy of
the radio access point.
10. A radio access point testing apparatus as defined in claim 9,
wherein said control unit evaluates the difference by using a value
obtained by converting the transmission power into power of an
antenna end of the radio access point.
11. A radio access point testing apparatus as defined in claim 9,
wherein said control unit judges that the radio access point is
normal, in a case where the evaluated difference is smaller than
the predetermined threshold value, and judges that the radio access
point is abnormal, in a case where the evaluated difference is not
smaller than the predetermined threshold value.
12. A radio access point testing apparatus as defined in claim 2,
further comprising: a noise generation portion which generates
noise; and a combiner which generates a test signal by superposing
the noise from said noise generation portion, on a signal outputted
from said terminal function portion, and which outputs the test
signal to said radio processing unit; wherein said terminal
function portion adjusts the transmission power so as to satisfy a
desired packet error rate or signal-to-noise ratio; and the
transmission power from said terminal function portion is set at
power which is higher than the reception power measured by said
measurement part or external noise, by superposing the noise.
13. A radio access point testing apparatus as defined in claim 12,
wherein: a signal quality of the test signal is set at a value
which is required for satisfying the desired packet error rate and
which has a small margin; and a packet error rate of the test
signal is measured, and the normalcy and abnormalcy of the radio
access point is judged depending upon whether or not the measured
packet error rate satisfies the desired packet error rate.
14. A radio access point testing apparatus as defined in claim 12,
further comprising a second attenuator which adjusts a magnitude of
the noise component from said noise generation portion.
15. A radio access point testing apparatus, comprising: a terminal
function portion which has a transmission function and a reception
function of a communication terminal in a radio communication
system; a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves; and a control unit which performs a
calling connection between said terminal function portion and a
predetermined device, through said radio processing unit, so as to
test normalcy and abnormalcy of a radio access point; wherein said
control unit obtains a difference between a value of the reception
power measured by said measurement part and transmission power of
said terminal function portion adjusted so as to satisfy a desired
packet error rate in said radio processing unit, and compares the
obtained difference and a predetermined threshold value, thereby to
judge the normalcy of the radio access point.
16. A radio access point testing apparatus, comprising: a terminal
function portion which has a transmission function and a reception
function of a communication terminal in a radio communication
system; a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves; a control unit which performs a calling
connection between said terminal function portion and a
predetermined device, through said radio processing unit, so as to
test normalcy and abnormalcy of a radio access point; a noise
generation portion which generates noise; and a combiner which
generates a test signal by superposing the noise from said noise
generation portion, on a signal outputted from said terminal
function portion, and which outputs the test signal to said radio
processing unit; wherein said terminal function portion adjusts the
transmission power so as to satisfy a desired packet error rate or
signal-to-noise ratio; and the transmission power from said
terminal function portion is set at power which is higher than the
reception power measured by said measurement part or external
noise, by superposing the noise.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a radio access point
testing apparatus, and more particularly to a radio access point
testing apparatus which confirms the normalcy of the radio
characteristic of a radio access point in an environment where
interfering waves such as external noise mix into the radio access
point in a mobile communication system employing a CDMA format.
[0002] In servicing the mobile communication system, the stability
of the system is one of important factors. For the stable operation
of the system, it is required to prevent the occurrence of any
failure leading to a system service shutdown, and also to promptly
detect the failure and resume the system operation in case of the
occurrence of the failure. Accordingly, the failure detection of
the radio access point and a diagnostic scheme therefor are very
important.
[0003] As an example of a method for diagnosing the normalcy of the
radio access point, JP-A-2002-271280 (Patent Document 1) discloses
a method wherein the normalcy of the radio access point is judged
in such a way that packet data are transmitted from a maintenance
terminal through the Internet to an access terminal which is
connected in branch from the antenna of the radio access point, and
that a reply from the access terminal is confirmed.
[0004] This method is really capable of detecting such an
abnormalcy as the complete cutoff of a main signal line in the
radio access point apparatus, but it is difficult of detecting such
a trifling abnormal state as some degradation in the radio
characteristic.
[0005] A transmitter and a receiver are mounted in the radio access
point. Regarding the failure of the transmitter of them, the
degradation of the radio characteristic can be detected
comparatively easily by monitoring signal power in a reverse link
(in a direction from the access point toward the access terminal).
In a forward link (in a direction from the access terminal toward
the access point), however, the level of the signal power in a
normal condition sometimes becomes a level lower than thermal
noise, especially in case of employing the CDMA as a radio
communication format, so that the abnormal state is difficult of
detection even when the radio characteristic has somewhat
degraded.
[0006] As a method for solving this problem, a method capable of
detecting the abnormal state is disclosed in JP-A-2005-151189
(Patent Document 2). More specifically, a testing access terminal
is connected in branch from the antenna port of the radio access
point. The testing access terminal controls transmission power so
that the packet error rate of sent packets may become constant, and
it confirms the transmission power of this testing access terminal
at the time when the packet error rate has fallen within a
predetermined range. Thus, even when the degradation of the radio
characteristic has occurred, the detection of the abnormal state is
possible. By way of example, if the transmission power of the
testing access terminal is high, degradation in the reception
sensitivity of the radio access point is judged.
SUMMARY OF THE INVENTION
[0007] Even with the method disclosed in Patent Document 2,
however, the transmission power of the packets which are sent from
the testing access terminal is controlled to be steadily high, in
such a case where interference waves from any other system arrive
in an environment in which the access point is located, or where
the number of terminals which are connected is large, so that
received power (RSSI: Received Signal Strength Indicator) in the
forward link is steadily high. On this occasion, it is difficult to
discriminate whether the high transmission power is influenced by
the external noise or is caused by the radio characteristic
degradation of the access point.
[0008] In consideration of the convenience of a maintenance
engineer side, the normalcy confirming test of the radio access
point should preferably be executable while the service of a radio
system is held continued. In this case, power from the general
terminals lying within a pertinent cell and interference power from
the other system enter the forward link as stated above. Therefore,
it is very possible that the RSSI in the forward link will heighten
temporarily or steadily. In the case where the access point
normalcy confirming test which employs the testing terminal is
carried out in the state of the high RSSI, problems to be mentioned
below are considered by way of example.
[0009] As one of the problems (the first problem), the test might
fail in a calling connection for the reason that an originating
signal from the testing terminal does not reach the access
point.
[0010] By way of example, there will be described a transmission
power control scheme for an access terminal, in "1x EV-DO" (short
for "1x Evolution Data Only", and refer to, for example, 3GPP2 C.
S. 0024 (Non-Patent Document 1) in detail) which is one of schemes
put to practical use as a third-generation portable phone system.
In the 1.times.EV-DO scheme, the initial transmission power of the
access terminal is determined by the strength of a reverse signal
transmitted from the access point, in the access terminal. By way
of example, if the reception power of the reverse signal in the
access terminal is high, it is judged that the access terminal lies
at a position near the access point, and the initial transmission
power in the access terminal is controlled to a low level. On the
other hand, if the reception power in the access terminal is low,
it is judged that the access terminal is far from the access point,
and the initial transmission power in the access terminal is
controlled to a high level. This control is called the "Open Loop
Power Control", and it is extensively used for the determination of
the initial transmission power in the access terminal, in the
mobile system employing the CDMA format. The initial transmission
power (Xo) of the access terminal in the 1x EV-DO scheme is
calculated by the following formula: Xo=-Mean Rx Power (dBm)+Open
Loop Adjust (dB)+Probe Initial Adjust (dB) (1)
[0011] Here, the "Mean Rx Power" denotes mean reception power in
the access terminal. The "Open Loop Adjust" and "Probe Initial
Adjust" are system parameters for adjusting the initial power, and
since both the parameters are uniquely determined by the system,
they cannot be adjusted every terminal. By way of example, the
initial transmission power (Xo) mentioned above is used as the
transmission power from the access terminal till the calling
connection.
[0012] More specifically, since the initial transmission power of
the access terminal is determined by the signal power of a reverse
link, the state of a forward link is not considered at all.
Therefore, when the RSSI in the access point is high in the forward
link on account of the interference waves from the other system,
the transmission power from the general terminals, or the like, the
initial transmission power from the testing access terminal is
excessively low relative to the RSSI, and the access point normalcy
confirming test fails in the calling connection in some cases. When
the calling connection from the testing access terminal ends in
failure, the access point normalcy confirming test ends in failure,
and hence, an abnormal state is decided by way of example. It is
difficult, however, to judge whether the decided abnormal state is
ascribable to the external noise or to any abnormalcy of the access
point apparatus. It is accordingly necessary to take a
countermeasure which prevents the failure in the calling connection
from the testing terminal, even under the environment where such
influence of the external noise is considered.
[0013] Even when the calling connection has been successful, the
other problem (the second problem) is involved in case of employing
the method stated in Patent Document 2. In the method, in order to
confirm the normalcy of the radio characteristic of the forward
link of the radio access point, the reception sensitivity in the
radio access point is measured on the basis of the transmission
power from the testing terminal as satisfies the desired packet
error rate in the forward link, and the normalcy of the reception
sensitivity in the radio access point is judged. In this case, a
normal decision result cannot be obtained, similarly under the
environment where the RSSI of the forward link is high.
[0014] Concretely, let's suppose a state where the RSSI of the
forward link is, for example, 10 dB higher than in an environment
in which quite no external noise exists. In a case where the
reception sensitivity measurement has been performed by the testing
access terminal in the state, the transmission power of the testing
access terminal is controlled to be higher in correspondence with
the rise (10 dB) of the RSSI of the forward link, in order to
attain the desired packet error rate. As the result of the
reception sensitivity test, therefore, the reception sensitivity of
the radio access point seems to have degraded 10 dB. Also here, it
is difficult to judge whether the abnormal state is ascribable to
the external noise or to any abnormalcy of the access point
apparatus. It is accordingly necessary to take a countermeasure
which prevents influence on the result of the radio characteristic
confirming test, even under the environment where such influence of
the external noise is considered.
[0015] In view of the above points, the present invention has for
its object to provide a radio access point testing apparatus which
excludes the influence of external noise, and which can carry out
the normalcy confirming test of a radio access point even under an
environment where the external noise exists. Another object of the
invention is to carry out a test normally without the influence of
external noise on a test result. Still another object of the
invention is to specify any abnormal test result as being
ascribable to the abnormalcy of the side of a radio access point
apparatus, not to the influence of external noise.
[0016] First, one means for resolution (first means) in the case
where a calling connection ends in failure under the influence of
external noise, as one of the problems (the first problem), will be
explained below.
[0017] The reason why the calling connection might end in the
failure when reception power RSSI in a forward link has heightened
under the influence of external noise or the like, is that, as
stated before by way of example, the initial transmission power of
an originating signal transmitted from an access terminal (a
general access terminal or a testing access terminal) is determined
by the strength of signal power in a reverse link, without
considering the state of a forward link. Therefore, when the
calling connection is performed in the state where the RSSI of the
forward link has heightened, the transmission power from the
testing access terminal might fail to reach a radio access
point.
[0018] As one means for solving this problem (first means), the
RSSI of the forward link is always monitored in the receiver of the
radio access point. In a case where the rise of the monitored RSSI
from RSSI in a state in which the external noise is nonexistent
exceeds a threshold value, a path loss in the signal path of the
reverse link as is fed to the testing access terminal is increased
by a quantity corresponding to the rise of the RSSI of the forward
link. In a case where a forward signal has not reached the access
point, the access terminal repeats retries by raising the power
about 10 to 20 dB ordinarily. Therefore, the threshold value can be
set at approximately 5 to 10 dB. Thus, the path loss of the reverse
link increases, whereby the reception power of the reverse link in
the testing access terminal lowers. As a result, the initial
transmission power (Xo) of the testing access terminal evaluated by
Formula (I) mentioned before increases by the decrease in the
reception power of the reverse link. Accordingly, the radio wave of
the testing access terminal can be caused to reach the receiver of
the radio access point, against the influence of the external
noise, and the calling connection can be performed.
[0019] As the other means (second means) for solving the first
problem, the access terminal of a general user calculates the
initial transmission power by Formula (I) mentioned before, whereas
the initial transmission power of the testing access terminal is
not evaluated by Formula (I), but it is given as a fixed value
which is the optimum value evaluated from the path loss between the
radio access point and the testing access terminal. Since the path
loss between the testing access terminal and the radio access point
does not change with time, this means can be adopted. Besides, on
this occasion, in a case where the RSSI (X) of the forward link has
risen to exceed a threshold value, on account of the external noise
or the like, the initial transmission power (Xo) given as the fixed
value is raised by an offset component (.DELTA.X) corresponding to
the rise of the RSSI of the forward link (to Xo+.DELTA.X), whereby
the initial transmission power is adjusted. Likewise to the first
means explained above, the radio wave of the testing access
terminal can be caused to reach the radio access point, against the
influence of the external noise, and the calling connection can be
performed.
[0020] Next, means (first means) for avoiding the influence of the
external noise in the case where the normalcy of the radio
characteristic of the forward link is confirmed, the influence
forming the other problem (the second problem), will be explained
below.
[0021] The reason why the external noise exerts the influence on
the normalcy confirming test of the radio characteristic of the
forward link, is that the transmission power of the testing access
terminal for satisfying the desired packet error rate rises when
the RSSI of the forward link rises. The problem on this occasion is
that whether the rise of the transmission power of the testing
access terminal is ascribable to the influence of the external
noise or to the abnormalcy of the radio access point apparatus
cannot be judged.
[0022] One (first means) of the means for solving the problem is a
method in which the normalcy of the radio characteristic is not
decided by the absolute value of the transmission power of the
testing access terminal, but it is evaluated by the ratio (relative
value) between the RSSI of the forward link measured in the radio
access point and a value (reception sensitivity level) obtained by
calculating the transmission power of the testing access terminal
into the power of the antenna end of the radio access point. A
formula for deciding the normalcy of the radio characteristic in
this case is as follows: Reception sensitivity level
(dBm)-RSSI(dBm)<Threshold value (dB) (2)
[0023] Thus, even in such a case where the RSSI of the forward link
has risen due to the external noise or the like, the normalcy of
the radio characteristic can be confirmed.
[0024] By the way, in the case where this method is employed, it
should more preferably be guaranteed that the value of the RSSI of
the forward link as has been measured in the radio access point is
correct. The reason therefor is as stated below. The measured RSSI
can indicate a value higher than an actual value on account of the
abnormalcy of the radio access point apparatus, especially the RSSI
measurement circuit portion thereof. Nevertheless, even when the
reception sensitivity level has somewhat risen on account of such
an abnormalcy of the radio access point apparatus, it might be
misdecided that the measurement value of the RSSI has risen by
above the rise of the reception sensitivity level, so the radio
access point apparatus is normal.
[0025] In order to avoid this problem, there is disposed means for
transmitting a signal at known fixed transmission power from the
testing access terminal, so as to confirm that the measurement
result of the RSSI measured in the radio access point is correct.
In this case, the set value of the fixed transmission power is set
at a level which is sufficiently higher than the rise of the RSSI
attributed to the external noise, whereby the influence of the
external noise exerted on the RSSI measurement value in the radio
access point can be neglected. Besides, the fixed transmission
power from the testing access terminal is inputted to the
receiver-0 and receiver-1 of the radio access point independently
of each other, whereby the influence on a service under operation
is suppressed to the minimum.
[0026] The other means (second means) for solving the second
problem is to superpose white noise on a signal from the testing
access terminal, whereby the test signal is fed to the radio access
point as a signal which, in itself, holds a certain CIR (Carrier to
Interference Ratio), and this test signal is set at a sufficiently
high level relative to the external noise. With this method, the
white noise of known level can be employed, so that the reception
quality of the test signal from the testing access terminal can be
calculated more precisely than in the first resolution means stated
above. The CIR of the test signal is determined by the ratio
between the level of the white noise and the transmission level of
the test signal, and it is adjusted to a value which is required
for satisfying a desired PER and which does not have a very wide
margin. Thus, in a case where the degradation of the radio
characteristic has occurred due to any hardware failure, it appears
as the degradation of a PER in the forward link, and hence, the
abnormalcy of the radio characteristic can be decided.
[0027] According to the first solving means of this invention,
there is provided a radio access point testing apparatus,
comprising:
[0028] a terminal function portion which has a transmission
function and a reception function of a communication terminal in a
radio communication system, and an initial transmission power from
the terminal function portion in case of performing a calling
connection is determined in accordance with reception power;
[0029] a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves;
[0030] an attenuator which adjusts a path loss between said
transmitter and said terminal function portion; and
[0031] a control unit which performs the calling connection between
said terminal function portion and a predetermined device, through
said radio processing unit, so as to test normalcy and abnormalcy
of a radio access point;
[0032] wherein
[0033] said attenuator increases the path loss in accordance with a
value of the reception power measured in said measurement part,
thereby to decrease the reception power in said terminal function
portion and to consequently increase the initial transmission
power;
[0034] said terminal function portion performs the calling
connection with the predetermined device by the increased initial
transmission power; and
[0035] said control unit performs the test of the radio access
point.
[0036] According to the second solving means of this invention,
there is provided a radio access point testing apparatus,
comprising:
[0037] a terminal function portion which has a transmission
function and a reception function of a communication terminal in a
radio communication system, and an initial transmission power in
case of performing a calling connection is previously set;
[0038] a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves; and
[0039] a control unit which performs the calling connection between
said terminal function portion and a predetermined device, through
said radio processing unit, so as to test normalcy and abnormalcy
of a radio access point;
[0040] wherein
[0041] said terminal function portion increases the set initial
transmission power in accordance with a value of the reception
power measured by said measurement part;
[0042] said terminal function portion performs the calling
connection with the predetermined device by the increased initial
transmission power; and
[0043] said control unit performs the test of the radio access
point.
[0044] According to the third solving means of this invention,
there is provided a radio access point testing apparatus,
comprising:
[0045] a terminal function portion which has a transmission
function and a reception function of a communication terminal in a
radio communication system;
[0046] a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves; and
[0047] a control unit which performs a calling connection between
said terminal function portion and a predetermined device, through
said radio processing unit, so as to test normalcy and abnormalcy
of a radio access point;
[0048] wherein said control unit
[0049] obtains a difference between a value of the reception power
measured by said measurement part and transmission power of said
terminal function portion adjusted so as to satisfy a desired
packet error rate in said radio processing unit, and
[0050] compares the obtained difference and a predetermined
threshold value, thereby to judge the normalcy of the radio access
point.
[0051] According to the forth solving means of this invention,
there is provided a radio access point testing apparatus,
comprising:
[0052] a terminal function portion which has a transmission
function and a reception function of a communication terminal in a
radio communication system;
[0053] a radio processing unit which includes a transmitter for
transmitting signals to said terminal function portion and the
communication terminal, a receiver for receiving signals from said
terminal function portion and the communication terminal, and a
measurement part for measuring reception power in said receiver as
includes power of the radio signal from the communication terminal
and/or interference waves;
[0054] a control unit which performs a calling connection between
said terminal function portion and a predetermined device, through
said radio processing unit, so as to test normalcy and abnormalcy
of a radio access point;
[0055] a noise generation portion which generates noise; and
[0056] a combiner which generates a test signal by superposing the
noise from said noise generation portion, on a signal outputted
from said terminal function portion, and which outputs the test
signal to said radio processing unit;
[0057] wherein
[0058] said terminal function portion adjusts the transmission
power so as to satisfy a desired packet error rate or
signal-to-noise ratio; and
[0059] the transmission power from said terminal function portion
is set at power which is higher than the reception power measured
by said measurement part or external noise, by superposing the
noise.
[0060] According to the present invention, it can provide a radio
access point testing apparatus which excludes the influence of
external noise, and which can carry out the normalcy confirming
test of a radio access point even under an environment where the
external noise exists. According to the present invention, it can
carry out a test normally without the influence of external noise
on a test result. Still another object of the invention is to
specify any abnormal test result as being ascribable to the
abnormalcy of the side of a radio access point apparatus, not to
the influence of external noise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0061] FIG. 1 is a diagram showing the configuration of a radio
access point testing system in an embodiment of the present
invention;
[0062] FIG. 2 is a block arrangement diagram (#1) of a radio access
point in the case of performing the reception characteristic
diagnosis of the loop-0 of a sector-1 in an embodiment of the
invention;
[0063] FIG. 3 is a block arrangement diagram (#2) of a radio access
point in the case of performing the reception characteristic
diagnosis of the loop-0 of a sector-1 in an embodiment of the
invention; and
[0064] FIG. 4 is a diagram for explaining a test sequence in the
case of performing the reception characteristic diagnosis of the
loop-0 in an embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
1. First Embodiment
(System Configuration)
[0065] The configurations and operating methods of a radio access
point apparatus and a radio communication network according to this
embodiment will be described in detail by taking a 1.times.EV-DO
(1.times. Evolution Data Only) system as an example.
[0066] FIG. 1 is a configurational diagram of a radio access point
testing system in the 1x EV-DO system.
[0067] The radio access point testing system includes a radio
access point to-be-tested (radio access point testing apparatus)
104, a center point facility 120, a test server 133 which is
connected to a network 132, and a maintenance terminal 131 which
monitors the radio access point 104 and the center point facility
120. The radio access point 104 takes a three-sector configuration
in this example, and it includes radio processing units 105-107
corresponding to respective sectors, a line interface (I/F) unit
108, a testing access terminal (testing terminal) 109, and an
access point control unit 110. The center point facility 120
includes a line I/F device 121 which accommodates the radio access
point 104, a switch (SW) unit 123 which performs the routing of
packets, a packet control device 122 which performs a packet
control and a session management, a authentication device 124 which
executes a terminal authentication (verification) process, and a
network interface (NW I/F) device 125 which performs connection
with the Internet. Incidentally, a plurality of radio access points
104 can also be disposed, and the individual radio access points
104 can be respectively connected to the center point 120.
[0068] The maintenance terminal 131 is connected to the access
point 104 via a maintenance network 130, and it has the function of
remotely monitoring and controlling the radio access point 104. The
test server 133 is, for example, a testing server, and a terminal
function portion within the testing access terminal 109 is
connected to the test server 133 via the network 132. Incidentally,
any appropriate server may be employed as the testing server.
[0069] The normalcy of the radio access point 104 is confirmed by
employing, for example, the testing access terminal 109 mounted in
the radio access point 104, and transmitting and receiving test
packets between this access terminal 109 and the test server 133.
The instruction of a test is given in such a way that the sector to
be tested is sent from the maintenance terminal 131 to the access
point control unit 110 of the radio access point 104. Upon
receiving the test instruction from the maintenance terminal 131,
the access point control unit 110 instructs the testing access
terminal 109 to transmit test data to the specified sector. The
testing access terminal 109 performs a calling connection with the
test server 133 through the specified one of the sectors 105-107.
After the completion of the calling connection, the testing access
terminal 109 transmits the test data to the test server 133 so as
to perform the normalcy confirming test of the access point 104.
Incidentally, the processing example of the normalcy confirming
test will be explained later. When a series of test steps have
ended, the access point control unit 110 reports a test result to
the maintenance terminal 131, and the maintenance terminal 131
displays the reported result on a screen by way of example. The
normalcy test of the radio access point 104 is ended by the above
flow.
[0070] FIG. 2 is a detailed configurational diagram of the access
point 104.
[0071] The sector-1 radio processing unit 105 of the access point
104 includes a radio signal transmission/reception portion 204 and
a modulation/demodulation process portion 217, and a loop-0 antenna
201 for both transmission and reception and a loop-1 antenna 202
for reception, for example, are connected to this radio processing
unit 105. The radio signal transmission/reception portion 204
includes a path switching part 207 for switching
transmission/reception paths, and a transmitter 212 of one loop and
receivers of two loops (receiver-0 213 and receiver-1 215).
Further, the radio signal transmission/reception portion 204
includes a DUP (duplexer) 205 which separates a reverse radio
signal and a forward radio signal, and a BPF (band-pass filter) 206
which limits the pass band of the forward radio signal.
Incidentally, the number of the sectors is not limited to three,
but one sector or any other appropriate number of sectors may well
be disposed. Besides, the receivers and the transmitter may well
have any other appropriate numbers of loops.
[0072] The transmitter 212 converts a reverse baseband signal
inputted from a modulator 218, into the reverse radio signal. The
receiver-0 213 receives the forward radio signal transmitted from
the access terminal, through the DUP 205, and it converts the
received radio signal into a forward baseband signal. The
receiver-1 215 receives the forward radio signal transmitted from
the access terminal, through the BPF 206, and it converts the
received radio signal into the forward baseband signal. The
receiver-0 213 and receiver-1 215 include RSSI measurement parts
214 and 216 for measuring the RSSIs of the received signals,
respectively. Incidentally, since the configuration of each of the
sector-2 radio processing unit 106 and sector-3 radio processing
unit 107 can be made identical to the configuration of the sector-1
radio processing unit 105, it shall be omitted from
description.
[0073] The modulation/demodulation process portion 217 includes the
modulator 218 and a demodulator 219, and it modulates and
demodulates data. The line interface unit 108 is the interface
between the radio access point 104 and the center point 120. The
access point control unit 110 has the functions of monitoring and
controlling the radio access point 104.
[0074] The testing access terminal 109 includes, for example, a
terminal function portion 233, a test function control portion 234,
a variable attenuator 231 for a forward path, and a variable
attenuator 232 for a reverse path. The terminal function portion
233 is a testing terminal which has, for example, functions
equivalent to those of an access terminal that is used by a general
user. By way of example, the terminal function portion 233 includes
a transmitter and a receiver. The test function control portion 234
has the function of controlling the terminal function portion 233.
By the way, in FIG. 2, the testing access terminal 109 may well
include a switch for switching connection to the sector
to-be-tested.
[0075] The path switching part 207 includes, for example, a
plurality of couplers (CPLs) 208, 209 and 210, and a switch (SW)
211. The CPL 208 connects the transmitter 212, the DUP 205 (or a
path to the antenna 201) and the variable attenuator 232 of the
reverse path (or a path to the testing access terminal 109) with
one another. Besides, the CPL 209 connects the receiver-0 213, the
DUP 205 (or the path to the antenna 201) and the SW 211 (or a path
to the testing access terminal 109) with one another. The CPL 210
connects the receiver-1 215, the BPF 206 (or a path to the antenna
202) and the SW 211 (or the path to the testing access terminal
109) with one another.
[0076] The CPL 208 extracts part of the reverse radio signal, and
outputs the extracted part to the testing access terminal 109.
Besides, the CPL 209 outputs a forward test signal transmitted from
the testing access terminal 109, to the receiver-0 213. The CPL 210
outputs a forward test signal transmitted from the testing access
terminal 109, to the receiver-1 215. The SW 211 switches whether
the testing access terminal 109 is to be connected to the
receiver-0 213 or to the receiver-1 215. This SW 211 can be
changed-over by, for example, the access point control unit 110 or
the test function control portion 234.
(Normalcy Confirming Test)
[0077] The processing of a reception sensitivity measurement test
will be explained as an example of a normality confirming test.
[0078] When the access point control unit 110 receives from the
maintenance terminal 131, a test start instruction which contains
the identification information of a sector to-be-tested and/or the
identification information of a loop (for example, loop 0 or loop
1), it transmits to the test function control portion 234, a switch
changeover instruction which contains the sector identification
information and/or the loop identification information.
Incidentally, the test start instruction may well contain test sort
information which indicates the reception sensitivity measurement
test. The test function control portion 234 receives the switch
changeover instruction, and it sets the SW 211 and the appropriate
switches so that the sector and/or the loop thereof, corresponding
to the sector identification information and/or loop identification
information contained in the instruction, may be connected with the
terminal function portion 233. Besides, the test function control
portion 234 controls power attenuation magnitudes in the
forward-path variable attenuator 231 and reverse-path variable
attenuator 232 so as to simulate the environment of the terminal
function portion 233. By way of example, when the attenuation
magnitudes are made large, it can be simulated that the terminal
function portion 233 lies at a far position from the access point
104. The terminal function portion 233 establishes a calling
connection state with a predetermined device (for example, the test
server 133) through, for example, the radio processing unit 105,
and it transmits packets to the predetermined device.
[0079] The access point control unit 110 evaluates a packet error
rate (PER) in such a way that the number of error packets counted
by the radio signal transmission/reception portion 204 (signal
processing portion) is divided by the total number of received
packets. Subsequently, the access point control unit 110 instructs
the test function control portion 234 to alter transmission power
in accordance with the measured packet error rate. By way of
example, when the packet error rate is high, the instruction is
given so as to raise the transmission power. On the other hand,
when the packet error rate is low, the instruction is given so as
to lower the transmission power. In compliance with the instruction
from the access point control unit 110, the test function control
portion 234 alters the transmission power from the terminal
function portion 233. Subsequently, the test function control
portion 234 transmits a transmission power value P1 after the
alteration, to the access point control unit 110. The access point
control unit 110 receives the transmission power value P1, and
stores it in a storage portion.
[0080] The access point control unit 110 evaluates the packet error
rate again. This access point control unit 110 judges if the
evaluated packet error rate falls within a predetermined range. It
repeats the instruction of the alteration of the transmission
power, to the test function control portion 234, the reception of
the transmission power value P1 from the test function control
portion 234, and the storage of the transmission power value P1
until the packet error rate falls within the predetermined
range.
[0081] The access point control unit 110 calculates a reception
sensitivity on the basis of the transmission power value P1 at the
time when the packet error rate lies within the predetermined
range. By way of example, the reception sensitivity may well be
evaluated in such a way that a predetermined path loss value from
the terminal function portion 233 to the reception part 213 or 215
is read out of the storage portion, and that the path loss value is
subtracted from the transmission power value P1. Alternatively, as
will be explained later, the reception sensitivity may well be
evaluated on the basis of the transmission power value P1 and the
RSSI. The access point control unit 110 transmits to the
maintenance device 131, a test result which contains the calculated
reception sensitivity and/or a failure decision result based on the
reception sensitivity.
[0082] Incidentally, an appropriate test different from the above
processing may well be performed as the normalcy confirming test.
It is also allowed to employ a sequence which is disclosed in FIG.
8 of JP-A-2005-151189 (Patent Document 2).
(Operation)
[0083] The first means for solving the first problem will be
concretely described with reference to FIG. 2.
[0084] Now, operations in the case where the test of the radio
access point 104 is performed under an environment in which
external noise exists will be described along the configuration
shown in FIG. 2. When the external noise is received by the
antennas 201 and 202 of the radio access point 104, its noise power
is inputted to the receiver-0 213 through the duplexer (DUP) 205
and coupler (CPL) 209 in the case of the loop-0 antenna 201, and it
is inputted to the receiver-1 215 through the band-pass filter
(BPF) 206 and coupler (CPL) 210 in the case of the loop-1 antenna
202. The receiver-0 213 and receiver-1 215 are monitoring the
values of RSSIs in the corresponding reception loops by the
respective RSSI measurement parts 214 and 216, and they report the
values to the access point control unit 110.
[0085] Upon receiving the instruction of the performance of the
normalcy test of the radio access point 104 from the maintenance
terminal 131, the access point control unit 110 confirms the RSSI
measurement value (X) reported from the RSSI measurement part 214
or 216, and it decides whether or not the value (X) exceeds a
preset threshold value.
[0086] In a case, for example, where the measured RSSI exceeds the
threshold value on account of the rise of the RSSI under the
influence of the external noise or the like, the access point
control unit 110 calculates the difference .DELTA. (dB)=X (dBm)-N
(dBm) between the RSSI measurement value (X) and thermal noise
power (N) in the nonexistence of the external noise. Incidentally,
the thermal noise power (N) in the nonexistence of the external
noise can be set beforehand. Besides, the thermal noise power may
well be measured and stored beforehand by, for example, connecting
a terminator instead of the antenna before the operation. The
access point control unit 110 notifies the difference .DELTA. (dB)
to the test function control portion 234 as the rise of the RSSI.
The test function control portion 234 increases an attenuation
magnitude in such a way that the value A notified by the access
point control unit 110 is added to a steady-state set value of the
variable attenuator 232 for adjusting the path loss of the reverse
link.
[0087] The subsequent processing is the same as in the normalcy
confirming test stated before. In case of originating (calling
connection) from the terminal function portion 233, the reception
power of the reverse link decreases due to the increase of the path
loss. In view of Formula (I) mentioned before, therefore, initial
transmission power in the case where the terminal function portion
233 originates rises by the decrease in the reception power of the
reverse link. In the case, for example, where the RSSI has risen
under the influence of the external noise, the calling connection
can be performed.
[0088] Also, the first resolution means for the second problem can
be elucidated by employing the configuration in FIG. 2.
[0089] FIG. 4 shows the procedure of a radio characteristic test in
the first means for solving the first problem, and the first means
for solving the second problem. Now, a test sequence in the case of
confirming the normalcy of the receiver-0 of a certain sector will
be described in conjunction with FIG. 4.
[0090] First of all, a test start instruction is transmitted from
the maintenance terminal 131 to the access point control unit 110
(step 408). The test start instruction can contain, for example,
the identification information of the sector and the identification
information of the loop (here, the loop 0). Subsequent steps can be
executed for, for example, the designated sector. Upon receiving
the test start instruction, the access point control unit 110 first
sends an RSSI report request to the receiver-0 213 in order to
confirm the newest RSSI value (step 409). The receiver-0 213
measures the newest RSSI value with, for example, the reception of
an RSSI measurement instruction as an opportunity (step 410), and
it reports an RSSI measurement value to the access point control
unit 110 (step 411). The access point control unit 110 decides
whether or not the reported value of the RSSI exceeds the threshold
value. When the threshold value is exceeded, the access point
control unit 110 evaluates the difference .DELTA. (dB) from the
thermal noise power in the state where the external noise is
nonexistent.
[0091] Subsequently, in order to test the receiver-0 213, the
access point control unit 110 instructs the path switching part 207
to change-over a path so as to input a test signal from the testing
access terminal 109 to the receiver-0 213 (step 412). The path
switching part 207 sets the path to the receiver-0 213. By way of
example, it connects the SW 211 to the receiver-0 side thereof. The
access point control unit 110 notifies the difference .DELTA. (dB)
evaluated above, to the test function control portion 234 (step
413). That is, it notifies that the RSSI is higher than in a steady
state in correspondence with the difference A. The test function
control portion 234 instructs the variable attenuator 232 inserted
in the reverse link, to raise the set value of the attenuation
magnitude by the difference .DELTA. (dB) (step 414), and it reports
to the access point control unit 110, to the effect that the
attenuation magnitude has been normally set (step 415).
[0092] Thus, processing for compensating the influence of the
external noise is completed. Therefore, the access point control
unit 110 instructs the test function control portion 234 to perform
a reception sensitivity measurement (step 416). The test function
control portion 234 instructs the terminal function portion 233 to
perform a calling connection, and it performs the reception
sensitivity measurement test after the completion of the calling
connection. By way of example, a test signal is sent from the
terminal function portion 233 in compliance with an instruction
from the access point control unit 110, and a PER is measured by
the demodulator 219 within the modulation/demodulation process
portion 217 so as to check whether or not the PER is a value within
a desired range. In a case where the PER does not fall within the
desired range, the transmission power of the terminal function
portion 233 is adjusted, and the PER measurement is performed
again. The access point control unit 110 repeats this processing
until the PER falls within the desired range. Incidentally, the
details of the procedure of the reception sensitivity measurement
test is as stated before. The repeated processing of the reception
of the test start instruction, the switch changeover, the calling
connection, etc. may well be appropriately omitted. The
transmission power of the terminal function portion 233 satisfying
the desired forward-link PER (Packet Error Rate) is evaluated by
the series of operations.
[0093] Thereafter, the access point control unit 110 requests the
receiver-0 213 to report the measurement value of the RSSI again
(step 420). The receiver-0 213 performs the measurement of the RSSI
(step 421), and it reports the RSSI measurement value to the access
point control unit 402 (step 422). The access point control unit
110 compares the RSSI value measured before the performance of the
test and the RSSI value measured after the end of the test, and it
confirms that a fluctuating width is within an error range. In a
case where the RSSI measurement values before and after the
performance of the test are greatly different, the external noise
might have greatly fluctuated during the test. Therefore, a test
result at this time can be discarded by judging it as data of low
reliability. In order to enhance a measurement accuracy, the
measurement processing for the RSSI may well be executed, not only
before and after the performance of the test, but also during the
test frequently.
[0094] When it has been judged that the fluctuation of the RSSI is
small, the access point control unit 110 subsequently judges the
normalcy of the radio access point 104 in conformity with the
following formula (step 423): Signal quality=(Transmission power
(dBm) of Terminal function portion-Path loss (dB))-RSSI measurement
value (dBm)<Decision threshold value (3)
[0095] Here, the "transmission power of the terminal function
portion" in Formula (3) is transmission power at the transmission
port end of the terminal function portion 233. Besides, the "path
loss" is the difference between the path losses of the transmission
port end of the terminal function portion 233--the output end of
the coupler 209 and the end of the radio-access-point antenna port
201--the output end of the coupler 209 in FIG. 2. That is, a value
obtained by subtracting the "path loss" from the "transmission
power of the terminal function portion" becomes a value obtained by
converting the transmission power from the terminal function
portion 233, into reception power at the antenna end of the radio
access point.
[0096] The "signal quality" satisfying the desired PER is evaluated
by the difference between the calculated signal power at the
antenna port end and the RSSI value. This signal quality is
compared with the preset "decision threshold value", whereby the
normalcy is judged. By way of example, the access point control
unit 110 can judge the normalcy of the radio access point in a case
where the evaluated difference is smaller than the preset threshold
value, whereas it can judge the abnormalcy of the radio access
point in a case where the evaluated difference is not smaller than
the preset threshold value.
2. Second Embodiment
[0097] FIG. 3 shows the configuration of the second resolution
means for the second problem. In this embodiment, a test is
performed using a test signal in which thermal noise, for example,
is superposed on the test signal itself, and which is set at a
signal quality that will satisfy a desired PER or S/N
(signal-to-noise ratio). A terminal function portion has its
transmission power raised by superposing the thermal noise, in
order to control the transmission power so that the S/N, for
example, may become constant.
[0098] In the first embodiment, the noise component in the case of
evaluating the signal quality of the test signal is predominated by
the external noise component. Therefore, in a case where the
external noise fluctuates temporally, the precision of a
measurement result sometimes degrades. In contrast, in the second
embodiment, the noise of known level is added as the test signal,
and hence, a signal quality can be measured without being
influenced by the external noise.
[0099] The general configuration of a system is the same as in FIG.
1. A radio access point 104 takes a three-sector configuration in
this example, and it includes radio processing units 105-107
corresponding to respective sectors, a line interface (I/F) unit
108, a testing access terminal 330, and an access point control
unit 110. The radio processing units 105-107, the line interface
(I/F) unit 108 and the access point control unit 110 are the same
as in the first embodiment, respectively.
[0100] In order to fulfill the function of this means, the testing
access terminal 330 includes a terminal function portion 336, a
test function control portion 337, a variable attenuator 333 for a
forward path, and a variable attenuator 334 for a reverse path.
Further, it includes a noise generation portion 335, a variable
attenuator (second attenuator) 332 for adjusting the level of the
noise, and a combiner (CMB) 331. The terminal function portion 336,
the test function control portion 337, the variable attenuator 333
for the forward path, the variable attenuator 334 for the reverse
path are the same as the corresponding portions of the first
embodiment, respectively.
[0101] The adjustment of the signal quality of the test signal is
performed by the settings of the variable attenuators 332 and 333.
In case of confirming the normalcy of a receiver-0 313, the access
point control unit 110 first acquires the measurement value of an
RSSI value based on this receiver-0, prior to the performance of
the test. With the configuration in FIG. 3, in a case where the
RSSI measurement value is higher than a threshold value, a
difference .DELTA. from a value in a steady state is given as the
increase given to the variable attenuator 334 of the reverse link,
and it is also set as the decrease given to the variable
attenuators 332 and 333 of the forward link. That is, in the case
where the RSSI measurement value is high under the influence of the
external noise, the attenuation magnitude of the forward link is
decreased, and transmission power from the testing terminal is
raised. The test signal is set at a power level which is
sufficiently high relative to the RSSI value of the forward link.
Thus, the influence of the external noise can be avoided. The test
signal itself is combined by the CMB 331 with a noise component
generated by the noise generation portion 335, and is thereafter
fed to the radio processing unit 105.
[0102] According to this embodiment, the noise component of
sufficiently high level is fed as the test signal, so that the PER
measurement of the test signal can be performed without being
influenced by the external noise. Besides, in a case where the
abnormalcy of an apparatus side has taken place, the degradation of
the signal quality of the test signal occurs. Therefore, in a case
where the PER of the forward link is measured on the basis of the
test signal by a modulation/demodulation process portion 317 and
where a desired PER is satisfied, it can be judged that a radio
characteristic is normal. In contrast, in a case where the PER
measured by the modulation/demodulation process portion 317 does
not satisfy the desired PER, it can be judged that any abnormalcy
is involved in the radio access point apparatus.
3. Modification to First Embodiment
[0103] As the other means (second means) for solving the first
problem, the access terminal of a general user calculates the
initial transmission power by Formula (I) mentioned before, whereas
the initial transmission power of the testing access terminal 109
is not evaluated by Formula (I), but it is given as a fixed value
which is the optimum value evaluated from the path loss between the
radio access point 104 and the testing access terminal 109. Since
the path loss between the testing access terminal 109 and the radio
access point 104 does not change with time, this means can be
adopted. Besides, on this occasion, in a case where the RSSI (X) of
the forward link has risen to exceed a threshold value, on account
of the external noise or the like, the initial transmission power
(Xo) given as the fixed value is raised by an offset component
(.DELTA.X) corresponding to the rise of the RSSI of the forward
link (to Xo+.DELTA.X), whereby the initial transmission power is
adjusted. Likewise to the first means explained before, the radio
wave of the testing access terminal can be caused to reach the
radio access point, against the influence of the external noise,
and the calling connection can be performed.
[0104] Incidentally, the remaining configuration and processing can
be made the same as in the first embodiment by way of example.
4. Appendix
[0105] While the first to third embodiments have been described
above, the individual embodiments may well be combined, or parts of
the individual embodiments may well be combined in such a manner
that the third embodiment is employed for the calling connection in
the first embodiment.
[0106] According to the present invention, the reception
characteristic of a radio access point can be measured at a high
precision, remotely and on-line fashion without incurring a service
interruption and without being influenced by external noise.
Besides, in a case where a desired characteristic has not been
attained, a defective part can be specified.
[0107] The invention is applicable to, for example, an industry
which concerns a communication system for radio communications, and
an industry which provides a communication service by employing the
communication system.
* * * * *