U.S. patent application number 13/113296 was filed with the patent office on 2012-03-22 for radio frequency signal control module and radio frequency signal controlling method.
This patent application is currently assigned to MEDIATEK INC.. Invention is credited to Da-Wei Sung, Wen-Wei Yang.
Application Number | 20120071108 13/113296 |
Document ID | / |
Family ID | 45817740 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120071108 |
Kind Code |
A1 |
Yang; Wen-Wei ; et
al. |
March 22, 2012 |
Radio Frequency Signal Control Module and Radio Frequency Signal
Controlling Method
Abstract
A radio frequency (RF) signal control module is provided. The RF
signal control module includes a detection and control device
detecting at least one radio coupling value in a transmission band
according to a radio coupling signal and generating a control
signal for controlling transmission power an RF signal to be
transmitted according to the detected radio coupling value.
Inventors: |
Yang; Wen-Wei; (Jhubei City,
TW) ; Sung; Da-Wei; (Zhudong Township, TW) |
Assignee: |
MEDIATEK INC.
Hsin-Chu
TW
|
Family ID: |
45817740 |
Appl. No.: |
13/113296 |
Filed: |
May 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61384523 |
Sep 20, 2010 |
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Current U.S.
Class: |
455/68 |
Current CPC
Class: |
H04W 52/52 20130101;
H04W 52/16 20130101; H04W 52/18 20130101 |
Class at
Publication: |
455/68 |
International
Class: |
H04B 7/00 20060101
H04B007/00 |
Claims
1. A radio frequency (RF) signal control module, comprising: a
detection and control device, detecting at least one radio coupling
value in a transmission band according to a radio coupling signal
and generating a control signal for controlling transmission power
of an RF signal to be transmitted according to the detected radio
coupling value.
2. The RF signal control module as claimed in claim 1, further
comprising: a radio coupling device, obtaining the radio coupling
signal from a radio coupling path between a transmission antenna
utilized for transmitting the RF signal and the radio coupling
device.
3. The RF signal control module as claimed in claim 2, wherein the
radio coupling device is an antenna.
4. The RF signal control module as claimed in claim 2, wherein the
radio coupling device is a coupler.
5. The RF signal control module as claimed in claim 1, wherein the
radio coupling value is power of the radio coupling signal.
6. The RF signal control module as claimed in claim 1, wherein the
radio coupling value is a phase of the radio coupling signal.
7. The RF signal control module as claimed in claim 1, wherein the
radio coupling value is an impedance of a transmission antenna
utilized for transmitting the RF signal.
8. The RF signal control module as claimed in claim 1, wherein the
radio coupling signal is a faded version of the RF signal.
9. The RF signal control module as claimed in claim 1, wherein the
radio coupling signal is a reflected version of the RF signal.
10. The RF signal control module as claimed in claim 1, wherein the
radio coupling value is detected by measuring an S parameter
corresponding to a transmission antenna utilized for transmitting
the RF signal.
11. The RF signal control module as claimed in claim 1, wherein the
detection and control device further comprises: a memory, storing a
predetermined threshold value; a detector, detecting the radio
coupling value according to the radio coupling signal; a sampler,
sampling the detected radio coupling value to obtain a sampled
radio coupling value; and a comparator, comparing the sampled radio
coupling value with the predetermined threshold value and
generating the control signal according to a comparison result.
12. A radio frequency (RF) signal controlling method, comprising:
detecting an amount of change of a radio coupling value according
to a radio coupling signal; determining whether the amount of radio
coupling value change has exceeded a predetermined threshold; and
limiting a maximum transmission power of an RF signal to be
transmitted or lowering a transmission power of an RF signal to be
transmitted by a level when the amount of radio coupling value
change has exceeded the predetermined threshold.
13. The method as claimed in claim 12, further comprising:
obtaining the radio coupling signal from a radio coupling path
coupled to a transmission antenna utilized for transmitting an RF
signal.
14. The method as claimed in claim 12, wherein the radio coupling
signal is a faded version of the RF signal.
15. The method as claimed in claim 12, wherein the radio coupling
signal is a reflected version of the RF signal.
16. The method as claimed in claim 12, wherein the radio coupling
value is power of the radio coupling signal.
17. The method as claimed in claim 12, wherein the radio coupling
value is a phase of the radio coupling signal.
18. The method as claimed in claim 12, wherein the radio coupling
value is an impedance of a transmission antenna utilized for
transmitting the RF signal.
19. The method as claimed in claim 12, wherein the detecting step
further comprising: measuring an S parameter corresponding to a
transmission antenna utilized for transmitting an RF signal.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/384,523 filed Sep. 20, 2010 and entitled
"OMNI-DIRECTIONAL SAR CALIBRATION". The entire contents of which
are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a radio frequency (RF) signal
control module, and more particularly to an RF signal control
module that is capable of omni-directional detection of radio
coupling values and accordingly controlling the transmission power
of a communications device.
[0004] 2. Description of the Related Art
[0005] Specific absorption rate (SAR) is a measure of the rate at
which radio frequency (RF) energy is absorbed by a human body when
exposed to a radio-frequency electromagnetic field. It is defined
as the power absorbed per mass of tissue and has units of Watts per
kilogram. SAR is usually averaged either over the whole body, or
over a small sample volume (typically 1 g or 10 g of tissue). The
value cited is then the maximum level measured in the body part
studied over the stated volume or mass. It may be calculated from
the electric field within the tissue as:
SAR = .sigma. E 2 2 .rho. , ##EQU00001##
where .sigma. represents the sample electrical conductivity, |E|
represents the magnitude of the electric field and .rho. represents
the sample density.
[0006] Conventionally, a proximity sensor is embedded in an
electronic device for SAR calibration. Once the proximity sensor
has detected that a human body is close to the electronic device, a
maximum RF transmission power is limited. However, the proximity
sensor is a directional device. The more directions that are
required to be detected for calibration, the more proximity sensors
required to be provided.
[0007] Therefore, a novel design for transmission power detection
and control without directional limitations is highly required.
BRIEF SUMMARY OF THE INVENTION
[0008] A radio frequency (RF) signal control module and RF signal
controlling method are provided. An embodiment of an RF signal
control module comprises a detection and control device. The
detection and control device detects at least one radio coupling
value in a transmission band according to a radio coupling signal
and generates a control signal for controlling transmission power
of an RF signal to be transmitted according to the detected radio
coupling value.
[0009] An embodiment of an RF signal controlling method comprises:
detecting an amount of change of a radio coupling value according
to a radio coupling signal; determining whether the amount of radio
coupling value change has exceeded a predetermined threshold; and
limiting a maximum transmission power of an RF signal to be
transmitted or lowering a transmission power of an RF signal to be
transmitted by a level according to the detected radio coupling
value when the amount of radio coupling value change has exceeded
the predetermined threshold.
[0010] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The invention can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0012] FIG. 1 shows a schematic block diagram of a communications
apparatus according to an embodiment of the invention;
[0013] FIG. 2 shows a schematic block diagram of the RF signal
control module according to an embodiment of the invention;
[0014] FIG. 3 shows a schematic block diagram of a communications
apparatus according to an embodiment of the invention;
[0015] FIG. 4 shows a schematic block diagram of a communications
apparatus according to another embodiment of the invention;
[0016] FIG. 5 shows a schematic diagram of a coupler 528 according
to an embodiment of the invention;
[0017] FIG. 6 shows a schematic block diagram of the detection and
control device according to an embodiment of the invention;
[0018] FIG. 7 shows a schematic block diagram of a communications
apparatus equipped with multiple transmission antennas according to
another embodiment of the invention;
[0019] FIG. 8 shows a schematic block diagram of a communications
apparatus equipped with multiple transmission antennas according to
another embodiment of the invention; and
[0020] FIG. 9 shows a flow chart of an RF signal controlling method
according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. The scope of the invention
is best determined by reference to the appended claims.
[0022] FIG. 1 shows a schematic block diagram of a communications
apparatus according to an embodiment of the invention. The
communications apparatus 100 may at least comprise a transceiver
module 102 and a radio frequency (RF) signal control module 104.
The transceiver module 102 is arranged to generate an RF signal
S.sub.RF to be transmitted to the air interface. The RF signal
control module 104 is arranged to generate a control signal
S.sub.Ctrl to adjust transmission power utilized by the transceiver
module 102 for transmitting the RF signal S.sub.RF. It should be
noted that for clear illustration of the invention concept, only
the devices related to the proposed design are illustrated in FIG.
1, and therefore, the invention should not be limited thereto.
[0023] According to an embodiment of the invention, the RF signal
control module 104 obtains or receives a radio coupling signal
S.sub.Couple and generates the control signal S.sub.Ctrl according
to the radio coupling signal S.sub.Couple. In the embodiments of
the invention, the radio coupling signal S.sub.Couple is
corresponding to transmission of the RF signal S.sub.RF.
[0024] FIG. 2 shows a schematic block diagram of the RF signal
control module according to an embodiment of the invention. The RF
signal control module 104 may comprise a radio coupling device 202
and a detection and control device 204. The radio coupling device
202 is arranged to obtain or receive the radio coupling signal
S.sub.Couple in a transmission band through a radio coupling path
established between a transmission antenna transmitting the RF
signal S.sub.RF and the RF signal control module 104 (which will be
discussed in more detail in the following paragraphs). The
detection and control device 204 is arranged to detect at least one
radio coupling value according to the radio coupling signal
S.sub.Couple, and generates the control signal S.sub.Ctrl for
controlling transmission power of the RF signal S.sub.RF to be
transmitted later according to the detected radio coupling
value.
[0025] According to an embodiment of the invention, the radio
coupling device 202 may be implemented by a sensor antenna for
receiving the radio coupling signal S.sub.Couple. In the
embodiment, the radio coupling signal S.sub.Couple may be a faded
version of the RF signal S.sub.RF. FIG. 3 shows a schematic block
diagram of a communications apparatus 300 according to an
embodiment of the invention. As shown in FIG. 3, the transceiver
module 302 is coupled to a transmission antenna 324 for
transmitting the RF signal S.sub.RF generated thereby. Note that in
some embodiments, the transmission antenna 324 may also be
integrated in the transceiver module 302 and the invention should
not be limited thereto. The RF signal control module 104 may
comprise the detection and control device 304 and a sensor antenna
326. The transmitted RF signal S.sub.RF may be received by the
sensor antenna 326 from the radio coupling path 330 between the
transmission antenna 324 and the sensor antenna 326. Because the
radio coupling is omni-directional and fixed from the transmission
antenna 324 to the sensor antenna 326, according to an embodiment
of the invention, the detection and control device 304 may detect
and monitor the power or phase of the radio coupling signal
S.sub.Couple, or any other radio coupling value according to the
radio coupling signal S.sub.Couple, and determine whether a
currently detected radio coupling value has exceeded a
predetermined threshold determined when there is no human body
close to the communications apparatus 300. When the radio coupling
value is determined to have exceeded the predetermined threshold,
the detection and control device 304 may determine that there is at
least one human body close to the communications apparatus 300, and
generate the control signal S.sub.Ctrl for limiting the maximum
transmission power of the transceiver module 302 or lowering the
transmission power of the RF signal S.sub.RF to be transmitted
later by a certain level. Therefore, the possible RF energy
absorbed by the human body when exposed to radio frequency
electromagnetic field is reduced. Note that in some embodiments of
the invention, the predetermined threshold may also be set as an
amount of possible change of the radio coupling value determined
when there is no human body close to the communications apparatus
300. The detection and control device 304 may detect and monitor
the amount of change of the radio coupling value. When the amount
of radio coupling value change has exceeded the predetermined
threshold, the detection and control device 304 may determine that
there is at least one human body close to the communications
apparatus 300, and generate the control signal S.sub.Ctrl for
limiting the maximum transmission power of the transceiver module
302 or lowering the transmission power of the RF signal S.sub.RF to
be transmitted later by a certain level. Note also that in other
embodiments, the predetermined threshold may also be set as a
percentage or an absolute value of predetermined radio coupling
value or an amount of possible change of the radio coupling value
determined when there is no human body close to the communications
apparatus, or may be set as other values based on the similar
concepts, and the invention should not be limited to the examples
as described above.
[0026] According to an embodiment of the invention, an ideal radio
coupling value or the ideal amount of possible change of the radio
coupling value when there is no human body close to the
communications apparatus is first determined. For example, suppose
that when there is no human body close to the communications
apparatus 300, the power of the transmitted RF signal S.sub.RF is
23 dBm and the power of the received radio coupling signal
S.sub.Couple is -7 dBm, and therefore, the ideal radio coupling
path loss is obtained by (-7-23)=30 dBm. A 10% margin may be
applied, so that the predetermined threshold of the radio coupling
path loss may be determined as 33 dBm. In other words, once a
currently obtained radio coupling path loss determined by the
detection and control device 304 has exceeded 33 dBm, the detection
and control device 304 may determine that there is at least one
human body close to the communications apparatus 300, and generate
the control signal S.sub.Ctrl for limiting the maximum transmission
power of the transceiver module 302.
[0027] For another example, an ideal phase of the received radio
coupling signal S.sub.Couple may first be measured when there is no
human body close to the communications apparatus 300. The phase
component may be obtained from the imaginary part of the received
radio coupling signal S.sub.Couple. A suitable margin may also be
applied, so as to determine one or more predetermined thresholds
corresponding to the phase of the received radio coupling signal
S.sub.Couple. Once a currently obtained phase of the received radio
coupling signal S.sub.Couple is determined to be different from the
predetermined threshold(s), the detection and control device 304
may determine that there is at least one human body close to the
communications apparatus 300, and generate the control signal
S.sub.Ctrl for limiting the maximum transmission power of the
transceiver module 302 or lowering the transmission power of the RF
signal S.sub.RF to be transmitted later by a certain level.
[0028] According to another embodiment of the invention, the radio
coupling device 202 may be implemented by a coupler for obtaining
the radio coupling signal S.sub.Couple. In the embodiment, the
radio coupling signal S.sub.Couple may be a reflected (or returned)
version of the RF signal S.sub.RF. FIG. 4 shows a schematic block
diagram of a communications apparatus 400 according to another
embodiment of the invention. As shown in FIG. 4, a coupler 428 is
coupled between a transmission antenna 424 for transmitting the RF
signal S.sub.RF and a power amplifier 422. The power amplifier 422
is comprised in the transceiver module 402. Note that in some
embodiments, the transmission antenna 424 may also be integrated in
the transceiver module 402 and the invention should not be limited
thereto. Note also that in some embodiments, the coupler may be
integrated in the power amplifier 422, or embedded on the printed
circuit board, and the invention should not be limited thereto.
FIG. 5 shows a schematic diagram of a coupler 528 according to an
embodiment of the invention. The coupler 528 may comprise an input
port 501 for receiving the RF signal S.sub.RF from the power
amplifier 422, a transmitted port 502 for outputting the RF signal
S.sub.RF and receiving the reflected (or returned) RF signal
S'.sub.RF, a coupled port 503 for coupling the reflected (or
returned) RF signal S'.sub.RF to generate the radio coupling signal
S.sub.Couple and an isolated port 504. Referring back to FIG. 4,
according to an embodiment of the invention, the detection and
control device 404 may detect and monitor the power or phase of the
radio coupling signal S.sub.Couple, or any other radio coupling
value (such as an impedance of the transmission antenna 424)
according to the radio coupling signal S.sub.Couple, and determine
whether the radio coupling value or the amount of radio coupling
value change has exceeded a predetermined threshold determined when
there is no human body close to the communications apparatus 400.
When the radio coupling value or the amount of radio coupling value
change is determined to have exceeded the predetermined threshold,
the detection and control device 404 may determine that there is at
least one human body close to the communications apparatus 400, and
generate the control signal S.sub.Ctrl for limiting the maximum
transmission power of the transceiver module 402 or lowering the
transmission power of the RF signal S.sub.RF to be transmitted
later by a certain level. Therefore, the possible RF energy
absorbed by the human body when exposed to radio frequency
electromagnetic field is reduced.
[0029] For example, an ideal impedance of the transmission antenna
424 may first be measured when there is no human body close to the
communications apparatus 400. The impedance of the transmission
antenna 424 may be obtained by measuring an S parameter
corresponding to the transmission antenna 424. For example, when
the coupler 428 is a multi-port device with port 1 P1 and port 2
P2, the measured input return loss S.sub.11 may be representable of
the impedance of the transmission antenna 424. To be more specific,
the detection and control device 404 may obtain an ideal input
return loss S.sub.11 according to a ratio of the radio coupling
signal S.sub.Couple to the RF signal S.sub.RF when there is no
human body close to the communications apparatus 400. Suppose that
the obtained ideal input return loss S.sub.11 is expressed by
S.sub.11=a+bj, where the a and b are real numbers, and j is a
mathematical symbol which is called the imaginary unit. The
detection and control device 404 may take the imaginary part number
b as the radio coupling value to represent the impedance of the
transmission antenna 424. Similarly, a suitable margin may also be
applied, so as to determine the predetermined threshold
corresponding to the impedance of the transmission antenna 424.
Once a currently obtained input return loss S.sub.ii (or currently
obtained impedance of the transmission antenna 424) is determined
to have exceeded the predetermined threshold, the detection and
control device 404 may determine that there is at least one human
body close to the communications apparatus 400, and generate the
control signal S.sub.Ctrl for limiting the maximum transmission
power of the transceiver module 402 or lowering the transmission
power of the RF signal S.sub.RF to be transmitted later by a
certain level.
[0030] Note that in other embodiments of the invention, the other
information obtained from the measured input return loss S.sub.11
may also be taken as the radio coupling value. For example, the
real part number a, or a combination of the real part and imaginary
part numbers a and b, such as {square root over (a.sup.2+b.sup.2)},
may also be taken as the radio coupling value. Besides the input
return loss S.sub.11, the insertion loss S.sub.21 may also be
obtained as the radio coupling value and the invention should not
be limited thereto. For example, when the insertion loss S.sub.21
is expressed by S.sub.21=c+dj, where the c and d are real numbers,
the real part number c, the imaginary part number d, or a
combination of the real part and imaginary part numbers c and d,
such as {square root over (c.sup.2+d.sup.2)}, may also be taken as
the radio coupling value.
[0031] FIG. 6 shows a schematic block diagram of the detection and
control device according to an embodiment of the invention. The
detection and control device 604 may comprise a detector 641, a
sampler 642, a comparator 643 and a memory 644. According to an
embodiment of the invention, the detector 641 may receive the radio
coupling signal S.sub.Couple from the radio coupling device, and
detect the radio coupling value and/or the amount of radio coupling
value change according to the radio coupling signal S.sub.Couple.
For example, the detector 641 may detect the power and/or power
change of the radio coupling signal S.sub.Couple by performing
waveform to voltage conversion. For another example, the detector
641 may detect the phase and/or phase change of the radio coupling
signal S.sub.Couple by extracting the imaginary part of the radio
coupling signal S.sub.Couple. For yet another example, the detector
641 may detect the impedance and/or impedance change of the
transmission antenna by measuring the S parameter in the
transceiver network. The value S.sub.V detected by the detector 641
may further be sampled by the sampler 642. The sampler 642 may be,
for example, an analog to digital converter. The sampled value
S.sub.V' may be further passed to the comparator 643. The
comparator 643 may compare the sampled value S.sub.V' with a
predetermined threshold value TH stored in the memory 644, and
generate the control signal S.sub.Ctrl according to the comparison
result. Note that FIG. 6 only shows one exemplary design of the
detection and control device, and the invention should not be
limited thereto. In addition, in the embodiments of the invention,
the detection and control device may be implemented by dedicated
hardware, or the functions performed by the detection and control
device as described above may be coded as some software
instructions executed by a general purpose processor. Therefore,
the invention should not be limited to either cases.
[0032] FIG. 7 shows a schematic block diagram of a communications
apparatus equipped with multiple transmission antennas according to
another embodiment of the invention. The communications apparatus
700 may at least comprise two transmission antennas 724 and 726 for
simultaneously transmitting the RF signal (the MIMO case) or not
simultaneously transmitting the RF signal (the antenna selection
case). In the embodiment, two radio coupling devices 706 and 708
are utilized and disposed close to the transmission antennas 724
and 726 for detecting the radio coupling signals, respectively. For
example, for the MIMO case, both of the transmission antennas 724
and 726 are utilized for transmitting the RF signals. The radio
coupling devices 706 and 708 disposed close to the transmission
antennas 724 and 726 may respectively detect the radio coupling
signals reflected to the transmission antennas 724 and the
transmission antennas 726, or detect the radio coupling signal
coupled from the transmission antennas 726 (or 724) to the
transmission antennas 724 (or 726). For another example, for the
antenna selection case, when the transmission antennas 724 is
utilized for transmitting the RF signal and the transmission
antennas 726 is not utilized for transmitting the RF signal, the
radio coupling device 708 corresponding to the transmission
antennas 726 may be utilized to detect the radio coupling signal
coupled from the transmission antennas 724 to the transmission
antennas 726, and vise versa. The received coupling signals are
further transmitted to the detection and control device 704 for
transmission power control. It should be noted that FIG. 7 is a
simplified block diagram with a lot of devices configured inside of
the commutations device omitted for clear illustration of the
invention concept. Therefore, the invention should not be limited
thereto. It should also be noted that when there are more than one
transmission antenna utilized for transmitting the RF signals (for
example, the MIMO case), the radio coupling value(s) may be
obtained according to one radio coupling signal corresponding to
either one transmission antenna, or according to the radio coupling
signals obtained corresponding to the multiple transmission
antennas, or according to a combination result of the radio
coupling signals corresponding to multiple transmission antennas,
or others. The way to determine the predetermined threshold may
also be varied based on the mechanism of obtaining the radio
coupling value.
[0033] FIG. 8 shows a schematic block diagram of a communications
apparatus equipped with multiple transmission antennas according to
another embodiment of the invention. The communications apparatus
800 may at least comprise two transmission antennas 824 and 826 for
simultaneously transmitting the RF signal (the MIMO case) or not
simultaneously transmitting the RF signal (the antenna selection
case). In the embodiment, one radio coupling device 806 is utilized
and disposed close to (or between) the transmission antennas 824
and 826 for detecting the radio coupling signal. For example, for
the MIMO case, both of the transmission antennas 824 and 826 are
utilized for transmitting the RF signals. The radio coupling device
806 may detect the radio coupling signals reflected to the
transmission antennas 824 and the transmission antennas 826, or
detect the radio coupling signal coupled from the transmission
antennas 826 (or 824) to the transmission antennas 824 (or 826).
For another example, for the antenna selection case, when the
transmission antennas 824 is utilized for transmitting the RF
signal and the transmission antennas 826 is not utilized for
transmitting the RF signal, the radio coupling device 806 may be
utilized to detect the radio coupling signal coupled from the
transmission antennas 824 to the transmission antennas 826, and
vise versa. The received coupling signals are further transmitted
to the detection and control device 804 for transmission power
control. It should be noted that FIG. 8 is a simplified block
diagram with a lot of devices configured inside of the commutations
device omitted for clear illustration of the invention concept.
Therefore, the invention should not be limited thereto. It should
also be noted that in some embodiments of the invention, for the
antenna selection case as previously described, the transmission
antenna that is not utilized for transmitting the RF signal may
also function as the radio coupling device for receiving or
obtaining the radio coupling signal S.sub.Couple. In this case, a
dedicated radio coupling device (such as the radio coupling device
706, 708 or 806 as shown in FIG. 7 and FIG. 8) can be omitted.
[0034] FIG. 9 shows a flow chart of an RF signal controlling method
according to an embodiment of the invention. To begin, an amount of
change of a radio coupling value corresponding to a communications
apparatus may be detected according to a radio coupling signal
(Step S902). Next, it is determined whether the amount of radio
coupling value change has exceeded a predetermined threshold (Step
S904). When the amount of radio coupling value change has not
exceeded a predetermined threshold, it is determined that there is
no human body close to the corresponding communications apparatus
and the process may be ended. Otherwise, a maximum transmission
power of the communications apparatus for transmitting an RF signal
may be limited or a transmission power of the RF signal S.sub.RF to
be transmitted later may be lowered by a certain level according to
the amount of radio coupling value change (Step S906). Note that
when it is determined that there is any human body close to the
corresponding communications apparatus, the maximum transmission
power is limited to a smaller possible value as defined by the
corresponding specifications so as to reduce possible RF energy
absorbed by the human body. In other embodiments, the transmission
power of the communications apparatus for transmitting an RF signal
may also be directly reduced according to the detected radio
coupling value, and the invention should not be limited thereto.
The flow as shown in FIG. 9 may be repeated periodically, so as to
dynamically control the transmission power of the communications
apparatus.
[0035] The above-described embodiments of the present invention can
be implemented in any of numerous ways. For example, the
embodiments may be implemented using hardware, software or a
combination thereof. It should be appreciated that any component or
collection of components that perform the functions described above
can be generically considered as one or more processors that
control the above discussed function. The one or more processors
can be implemented in numerous ways, such as with dedicated
hardware, or with general purpose hardware that is programmed using
microcodes or software to perform the functions recited above.
[0036] While the invention has been described by way of example and
in terms of preferred embodiment, it is to be understood that the
invention is not limited thereto. Those who are skilled in this
technology can still make various alterations and modifications
without departing from the scope and spirit of this invention.
Therefore, the scope of the present invention shall be defined and
protected by the following claims and their equivalents.
* * * * *