U.S. patent application number 14/734508 was filed with the patent office on 2016-12-15 for systems and methods to control transmit power and specific absorption rate (sar) for wireless devices.
The applicant listed for this patent is Gerald R. Pelissier, Liam Prendergast, Liam B. Quinn. Invention is credited to Gerald R. Pelissier, Liam Prendergast, Liam B. Quinn.
Application Number | 20160365886 14/734508 |
Document ID | / |
Family ID | 57516223 |
Filed Date | 2016-12-15 |
United States Patent
Application |
20160365886 |
Kind Code |
A1 |
Prendergast; Liam ; et
al. |
December 15, 2016 |
Systems And Methods To Control Transmit Power And Specific
Absorption Rate (SAR) For Wireless Devices
Abstract
Systems and methods are provided that may be implemented to
utilize multiple sensors to intelligently control RF transmit power
and specific absorption rate (SAR) produced from a wireless-enabled
information handling system platform in the presence of a detected
nearby human body. The disclosed systems and methods may be
implemented in one example to avoid the poor performance and user
experience that results from a reduction in the information
handling system platform radio transmit power when it is not
necessary (due to false detection of a human body), or that results
when the platform transmit power is reduced too much and/or too
quickly when nearby proximity of an actual human body is
detected.
Inventors: |
Prendergast; Liam;
(Limerick, IE) ; Pelissier; Gerald R.; (Mendham,
NJ) ; Quinn; Liam B.; (Austin, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Prendergast; Liam
Pelissier; Gerald R.
Quinn; Liam B. |
Limerick
Mendham
Austin |
NJ
TX |
IE
US
US |
|
|
Family ID: |
57516223 |
Appl. No.: |
14/734508 |
Filed: |
June 9, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/367 20130101;
H04W 52/146 20130101; H04W 52/34 20130101; H04W 52/18 20130101;
H04B 1/3838 20130101 |
International
Class: |
H04B 1/3827 20060101
H04B001/3827; H04W 52/34 20060101 H04W052/34; H04W 52/18 20060101
H04W052/18 |
Claims
1. An information handling system platform, comprising: multiple
sensors that are each configured to react to a proximity of a human
user to the system platform by producing a sensor output signal
that is indicative of a proximity distance of the human user to the
system platform; one or more antenna elements; at least one
transmitter coupled to the one or more antenna elements and
configured to transmit radio frequency (RF) signals from each of
the antenna elements; and at least one processing device coupled to
the transmitter, the processing device being coupled to receive the
sensor output signals of the multiple sensors and to determine a
real time object proximity detection distance from each of the
multiple sensor output signals; where the at least one processing
device is further configured to control the transmitter to reduce
RF transmit power according to at least one proximity distance
sensing profile that defines a relationship between RF transmit
power reduction and the determined object proximity detection
distance according to the multiple sensor outputs; and where each
of the multiple sensors has a different effective range of human
body proximity detection distance; where the proximity distance
sensing profile includes a relationship between RF transmit power
reduction and multiple separate ranges of determined object
proximity detection distance that are each assigned to a
corresponding one of the multiple sensors; and where the at least
one processing device is further configured to: determine for each
given sensor of the multiple sensors if the real time object
proximity detection distance determined from the sensor output
signal of the given sensor is within the range of determined object
proximity detection distance that is assigned to that given sensor,
select the sensor output signal of the given sensor if it is
determined that the real time object proximity detection distance
determined from the sensor output signal of the given sensor is
within the range of determined object proximity detection distance
that is assigned to that given sensor, and control the transmitter
to reduce RF transmit power according to the at least one proximity
distance sensing profile as a function of the object proximity
detection distance determined based on the sensor output signal of
the given sensor and not based on the sensor output signal of any
other signal during the time that the real time object proximity
detection distance determined from the sensor output signal of the
given sensor is within the range of determined object proximity
detection distance that is assigned to that given sensor.
2. The system platform of claim 1, further comprising: a first
processing device configured to execute applications and operating
system (OS) for the system platform; a second processing device
coupled between the multiple sensors and the first processing
device, each of the sensors being configured to react to a
proximity of a human user to the system platform by providing a
sensor output signal to the second processing device that is
indicative of a proximity distance of the human user to the system
platform, the second processing device being configured to: receive
the sensor output signals of the multiple sensors and to determine
a real time object proximity detection distance from each of the
multiple sensor output signals, use the real time object proximity
detection distance determined from each of the multiple sensor
output signals to determine for each given sensor of the multiple
sensors if the real time object proximity detection distance
determined from the sensor output signal of the given sensor is
within the range of determined object proximity detection distance
that is assigned to that given sensor and select the sensor output
signal of the given sensor if it is determined that the real time
object proximity detection distance determined from the sensor
output signal of the given sensor is within the range of determined
object proximity detection distance that is assigned to that given
sensor, use the real time object proximity detection distance
determined from the selected sensor output signal to determine a
real time RF transmit power reduction value from the at least one
proximity distance sensing profile, and provide a command to the
first processing device that is indicative of the determined real
time RF transmit power reduction value to cause the first
processing device to output a corresponding RF transmit power
control signal that is indicative of the determined real time RF
transmit power reduction value; and at least one baseband
processing device coupled between the first processing device and
the transmitter, the baseband processing device being configured to
control the transmitter in real time to reduce RF transmit power in
response to the at least one RF transmit power control signal
provided by the first processing device.
3. (canceled)
4. (canceled)
5. The system platform of claim 1, where the proximity distance
sensing profile includes a blended relationship of different RF
transmit power reduction values derived from different sensors as a
function of proximity detection distance from the multiple
sensors.
6. The system platform of claim 5 where the proximity distance
sensing profile comprises a single fitted curve of RF transmit
power reduction value versus proximity detection distance, the
single fitted curve being determined from different individual RF
transmit power reduction value profiles for the corresponding
individual sensors at different proximity detection distance.
7. The system platform of claim 1, where the at least one
processing device is further configured to communicate with one or
more off-platform devices; and to determine proximity of a human
user to the system platform based at least in part on
communications with the one or more off-platform devices.
8. The system platform of claim 1, where the multiple sensors
comprise at least one motion sensor, at least one acoustic sensor,
at least one capacitive proximity sensor and at least one
fingerprint sensor.
9. The system platform of claim 1, where the at least one
transmitter is configured to transmit Wireless Wide Area Network
"WWAN" RF cellular signals from each of the antenna elements; and
where the at least one processing device is further configured to
control the transmitter to reduce WWAN'' RF cellular signal
transmit power according to the at least one proximity distance
sensing profile that defines a relationship between RF transmit
power reduction and the determined object proximity detection
according to the multiple sensor outputs.
10. The system platform of claim 1, where the information handling
system platform is a handheld device configured to be held by a
user at the same time that the at least one transmitter is
transmitting RF signals from each of the antenna elements.
11. A method of operating an information handling system platform,
comprising: using multiple sensors of the information handling
system platform to detect a proximity of a human user to the system
platform by producing a sensor output signal that is indicative of
a proximity distance of the human user to the system platform;
using at least one processing device of the information handling
system platform to receive the sensor output signals of the
multiple sensors and to determine a real time object proximity
detection distance from each of the multiple sensor output signals;
and using the at least one processing device of the information
handling system platform to control a transmitter of the
information handling system platform to reduce RF transmit power
from one or more antennas of the information handling system
platform according to at least one proximity distance sensing
profile that defines a relationship between RF transmit power
reduction and the determined object proximity detection distance
according to the multiple sensor outputs; where each of the
multiple sensors has a different effective range of human body
proximity detection distance; where the proximity distance sensing
profile includes a relationship between RF transmit power reduction
and multiple separate ranges of determined object proximity
detection distance that are each assigned to a corresponding one of
the multiple sensors; and where the method further comprises using
the at least one processing device to: determine for each given
sensor of the multiple sensors if the real time object proximity
detection distance determined from the sensor output signal of the
given sensor is within the range of determined object proximity
detection distance that is assigned to that given sensor, select
the sensor output signal of the given sensor if it is determined
that the real time object proximity detection distance determined
from the sensor output signal of the given sensor is within the
range of determined object proximity detection distance that is
assigned to that given sensor, and control the transmitter to
reduce RF transmit power according to the at least one proximity
distance sensing profile as a function of the object proximity
detection distance determined based on the sensor output signal of
the given sensor and not based on the sensor output signal of any
other signal during the time that the real time object proximity
detection distance determined from the sensor output signal of the
given sensor is within the range of determined object proximity
detection distance that is assigned to that given sensor.
12. The method of claim 11, further comprising: using a first
processing device configured to execute applications and operating
system (OS) for the system platform; using each of the sensors to
react to a proximity of a human user to the system platform by
providing to a second processing device of the information handling
system platform a sensor output signal that is indicative of a
proximity distance of the human user to the system platform; using
the second processing device to: receive the sensor output signals
of the multiple sensors and to determine a real time object
proximity detection distance from each of the multiple sensor
output signals, use the real time object proximity detection
distance determined from each of the multiple sensor output signals
to determine for each given sensor of the multiple sensors if the
real time object proximity detection distance determined from the
sensor output signal of the given sensor is within the range of
determined object proximity detection distance that is assigned to
that given sensor and select the sensor output signal of the given
sensor if it is determined that the real time object proximity
detection distance determined from the sensor output signal of the
given sensor is within the range of determined object proximity
detection distance that is assigned to the given sensor, use the
real time object proximity detection distance determined from the
selected sensor output signal to determine a real time RF transmit
power reduction value from at least one proximity distance sensing
profile, and provide a command to the first processing device that
is indicative of the determined real time RF transmit power
reduction value to cause the first processing device to output a
corresponding RF transmit power control signal to a baseband
processing device that is indicative of the determined real time RF
transmit power reduction value; and using the at least one baseband
processing device to control the transmitter in real time to reduce
RF transmit power in response to the at least one RF transmit power
control signal provided by the first processing device.
13. (canceled)
14. (canceled)
15. The method of claim 11, where the proximity distance sensing
profile includes a blended relationship of different RF transmit
power reduction values derived from different sensors as a function
of proximity detection distance from the multiple sensors.
16. The method of claim 15 where the proximity distance sensing
profile comprises a single fitted curve of RF transmit power
reduction value versus proximity detection distance, the single
fitted curve being determined from different individual RF transmit
power reduction value profiles for the corresponding individual
sensors at different proximity detection distance.
17. The method of claim 11, further comprising using the at least
one processing device to communicate with one or more off-platform
devices; and to determine proximity of a human user to the system
platform based at least in part on communications with the one or
more off-platform devices.
18. The method of claim 11, where the multiple sensors comprise at
least one motion sensor, at least one acoustic sensor, at least one
capacitive proximity sensor and at least one fingerprint
sensor.
19. The method of claim 11, further comprising: using the at least
one transmitter to transmit Wireless Wide Area Network "WWAN" RF
cellular signals from each of the antenna elements; and using the
at least one processing device to control the transmitter to reduce
WWAN'' RF cellular signal transmit power according to the at least
one proximity distance sensing profile that defines a relationship
between RF transmit power reduction and the determined object
proximity detection according to the multiple sensor outputs.
20. The method of claim 11, further comprising using the
transmitter to transmit RF signals from each of the antenna
elements at the same time that the information handling system
platform is being held by a user.
21. (canceled)
22. (canceled)
23. An information handling system platform, comprising: multiple
sensors that are each configured to react to a proximity of a human
user to the system platform by producing a sensor output signal
that is indicative of a proximity distance of the human user to the
system platform; one or more antenna elements; at least one
transmitter coupled to the one or more antenna elements and
configured to transmit radio frequency (RF) signals from each of
the antenna elements; and at least one processing device coupled to
the transmitter, the processing device being coupled to receive the
sensor output signals of the multiple sensors and to determine a
real time object proximity detection distance from each of the
multiple sensor output signals; where the at least one processing
device is further configured to control the transmitter to reduce
RF transmit power according to at least one proximity distance
sensing profile that defines a relationship between RF transmit
power reduction and the determined object proximity detection
distance according to the multiple sensor outputs; and where the at
least one processing device is further configured to receive
proximity-indicative signals from one or more proximity sensors
located on one or more off-platform devices; and to control the
transmitter to reduce RF transmit power based at least in part on
the received proximity-indicative signals from the one or more
proximity sensors located on one or more off-platform devices.
24. The system platform of claim 1, further comprising multiple
different antennas; and where the at least one processing device is
further configured to: control the transmitter to reduce RF
transmit power to a first one of the multiple different antennas
according to at least a first proximity distance sensing profile
that defines a relationship between RF transmit power reduction and
the determined object proximity detection distance according to the
multiple sensor outputs; and control the transmitter to reduce RF
transmit power to a second and different one of the multiple
different antennas according to at least a second and different
proximity distance sensing profile that defines a relationship
between RF transmit power reduction and the determined object
proximity detection distance according to the multiple sensor
outputs.
25. The system platform of claim 1, where the platform is
reconfigurable between two or more configurations in which at least
one of the multiple sensors is positioned in a different location
on the platform, the one or more antenna elements are positioned in
different locations on the platform, or a combination thereof;
where the platform further comprises multiple different antennas;
and where the at least one processing device is further configured
to: control the transmitter to reduce RF transmit power according
to at least a first proximity distance sensing profile that defines
a relationship between RF transmit power reduction and the
determined object proximity detection distance according to the
multiple sensor outputs when the platform is configured to be in a
first one of the two more different platform configurations; and
control the transmitter to reduce RF transmit power according to at
least a second and different proximity distance sensing profile
that defines a relationship between RF transmit power reduction and
the determined object proximity detection distance according to the
multiple sensor outputs when the platform is configured to be in a
second one of the two more different platform configurations.
26. An information handling system platform, comprising: multiple
sensors that are each configured to react to a proximity of a human
user to the system platform by producing a sensor output signal
that is indicative of a proximity distance of the human user to the
system platform; one or more antenna elements; at least one
transmitter coupled to the one or more antenna elements and
configured to transmit radio frequency (RF) signals from each of
the antenna elements; and at least one processing device coupled to
the transmitter, the processing device being coupled to receive the
sensor output signals of the multiple sensors and to determine a
real time object proximity detection distance from each of the
multiple sensor output signals; where the at least one processing
device is further configured to control the transmitter to reduce
RF transmit power according to at least one proximity distance
sensing profile that defines a relationship between RF transmit
power reduction and the determined object proximity detection
distance according to the multiple sensor outputs where the
proximity distance sensing profile includes a blended relationship
of different RF transmit power reduction values derived from
different sensors as a function of proximity detection distance
from the multiple sensors; and where the proximity distance sensing
profile comprises a lookup table of blended power reduction values
that are each calculated from average RF transmit power reduction
values for two or three sensors having adjacent effective object
distance detection ranges.
27. The system platform of claim 1, where the at least one
processing device is further configured to dynamically adjust the
output power reduction of the transmitter that has been determined
according to the proximity distance sensing profile by further
adjusting this determined output power reduction based on an
identity of radio frequency or frequency channel of (RF) signals
being transmitted from the one or more antenna elements, or a
tunable antenna band switching or impedance matching state, or a
combination thereof.
28. (canceled)
29. (canceled)
30. A method of operating an information handling system platform,
comprising: using multiple sensors of the information handling
system platform to detect a proximity of a human user to the system
platform by producing a sensor output signal that is indicative of
a proximity distance of the human user to the system platform;
using at least one processing device of the information handling
system platform to receive the sensor output signals of the
multiple sensors and to determine a real time object proximity
detection distance from each of the multiple sensor output signals;
and using the at least one processing device of the information
handling system platform to control a transmitter of the
information handling system platform to reduce RF transmit power
from one or more antennas of the information handling system
platform according to at least one proximity distance sensing
profile that defines a relationship between RF transmit power
reduction and the determined object proximity detection distance
according to the multiple sensor outputs; and using the at least
one processing device to receive proximity-indicative signals from
one or more proximity sensors located on one or more off-platform
devices; and to control the transmitter to reduce RF transmit power
based at least in part on the received proximity-indicative signals
from the one or more proximity sensors located on one or more
off-platform devices.
31. The method of claim 11, where the platform further comprises
multiple different antennas; and where the method further comprises
using the at least one processing device to: control the
transmitter to reduce RF transmit power to a first one of the
multiple different antennas according to at least a first proximity
distance sensing profile that defines a relationship between RF
transmit power reduction and the determined object proximity
detection distance according to the multiple sensor outputs; and
control the transmitter to reduce RF transmit power to a second and
different one of the multiple different antennas according to at
least a second and different proximity distance sensing profile
that defines a relationship between RF transmit power reduction and
the determined object proximity detection distance according to the
multiple sensor outputs.
32. The method of claim 11, where the platform is reconfigurable
between two or more configurations in which at least one of the
multiple sensors is positioned in a different location on the
platform, the one or more antenna elements are positioned in
different locations on the platform, or a combination thereof;
where the platform further comprises multiple different antennas;
and where the method further comprises using the at least one
processing device to: control the transmitter to reduce RF transmit
power according to at least a first proximity distance sensing
profile that defines a relationship between RF transmit power
reduction and the determined object proximity detection distance
according to the multiple sensor outputs when the platform is
configured to be in a first one of the two more different platform
configurations; and control the transmitter to reduce RF transmit
power according to at least a second and different proximity
distance sensing profile that defines a relationship between RF
transmit power reduction and the determined object proximity
detection distance according to the multiple sensor outputs when
the platform is configured to be in a second one of the two more
different platform configurations.
33. A method of operating an information handling system platform,
comprising: using multiple sensors of the information handling
system platform to detect a proximity of a human user to the system
platform by producing a sensor output signal that is indicative of
a proximity distance of the human user to the system platform;
using at least one processing device of the information handling
system platform to receive the sensor output signals of the
multiple sensors and to determine a real time object proximity
detection distance from each of the multiple sensor output signals;
and using the at least one processing device of the information
handling system platform to control a transmitter of the
information handling system platform to reduce RF transmit power
from one or more antennas of the information handling system
platform according to at least one proximity distance sensing
profile that defines a relationship between RF transmit power
reduction and the determined object proximity detection distance
according to the multiple sensor outputs; where the proximity
distance sensing profile includes a blended relationship of
different RF transmit power reduction values derived from different
sensors as a function of proximity detection distance from the
multiple sensors; and where the proximity distance sensing profile
comprises a lookup table of blended power reduction values that are
each calculated from average RF transmit power reduction values for
two or three sensors having adjacent effective object distance
detection ranges.
34. The method of claim 11, further comprising using the at least
one processing device is to dynamically adjust the output power
reduction of the transmitter that has been determined according to
the proximity distance sensing profile by further adjusting this
determined output power reduction based on an identity of radio
frequency or frequency channel of (RF) signals being transmitted
from the one or more antenna elements, or a tunable antenna band
switching or impedance matching state, or a combination thereof.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to information handling
systems and, more particularly, to wireless transmission from
information handling systems.
BACKGROUND
[0002] As the value and use of information continues to increase,
individuals and businesses seek additional ways to process and
store information. One option available to users is information
handling systems. An information handling system generally
processes, compiles, stores, and/or communicates information or
data for business, personal, or other purposes thereby allowing
users to take advantage of the value of the information. Because
technology and information handling needs and requirements vary
between different users or applications, information handling
systems may also vary regarding what information is handled, how
the information is handled, how much information is processed,
stored, or communicated, and how quickly and efficiently the
information may be processed, stored, or communicated. The
variations in information handling systems allow for information
handling systems to be general or configured for a specific user or
specific use such as financial transaction processing, airline
reservations, enterprise data storage, or global communications. In
addition, information handling systems may include a variety of
hardware and software components that may be configured to process,
store, and communicate information and may include one or more
computer systems, data storage systems, and networking systems.
[0003] Specific absorption rate (SAR) refers to the rate at which
radio frequency (RF) energy is absorbed by the human body, and is
used to measure the power absorbed from mobile wireless devices
such as cell phones, tablet computers, and notebook computers. Many
government agencies around the world have set maximum allowable SAR
value limits for such mobile devices when in use. To conform RF
emissions to these SAR limits while at the same time maximizing
wireless performance, a mobile device has been provided with a
single capacitive proximity sensor that detects close proximity of
an object such as a human body. A processor within the mobile
device has then been used to reduce wireless RF transmission power
from the mobile device when the capacitive proximity sensor detects
close proximity of a nearby object, but to allow higher RF
transmission power in the absence of the detection of a nearby
object.
[0004] Current methods and implementations for controlling SAR
utilize a single capacitive proximity sensor to control only the
power transmitted from the main WWAN/LTE transmit antenna of a
wireless device, and employ a binary detection mechanism to control
wireless RF transmission power based only on either detection or
non-detection of a nearby object. Since the capacitive proximity
sensor cannot reliably distinguish between a human body and a
non-human object proximity trigger event, wireless transmission
performance from the device can needlessly suffer when transmit
power is reduced due to the detected nearby presence of a non-human
object.
SUMMARY
[0005] Disclosed herein are systems and methods that may be
implemented to utilize multiple sensors to intelligently control
SAR produced from a wireless-enabled information handling system
platform (e.g., mobile wireless device such as tablet or notebook
computer, smart phone, etc.) in the presence of a detected nearby
human body, while also enabling optimal wireless RF transmit
performance from the platform when no nearby human body is
detected. The disclosed systems and methods may be so implemented
to be more robust than conventional SAR solutions employed for
mobile devices. For example, the disclosed systems and methods may
be implemented in one embodiment to avoid the poor performance and
user experience that results from a reduction in the information
handling system platform radio transmit power when it is not
necessary (due to false detection of a human body), or that results
when the platform transmit power is reduced too much and/or too
quickly when nearby proximity of an actual human body is detected.
Thus, the disclosed systems and methods may employ smart usage of
combinations of sensors to increase proximity detection field of
view and to reduce or substantially eliminate false proximity
detection positives and in one embodiment meet FCC or other
governmental agency SAR requirements for RF exposure without
significant platform performance degradation of wireless
feature/s.
[0006] The disclosed systems and methods may be implemented in one
exemplary embodiment to reliably detect the difference between
nearby proximity of an actual human body and a non-human proximity
trigger event, and without the need for multiple
peripherally-located capacitive SAR sensors located to distinguish
between human body and non-human proximity, e.g., such as 4 to 6
capacitive proximity sensors located around the periphery of a
wireless tablet device (depending on the size of the tablet device)
or other such smart form-factor, which may drive increased
complexity, increased cost and require more space for additional
capacitive electrodes with associated industrial design and
mechanical engineering impacts. Moreover, the disclosed systems and
methods may be implemented in a scalable manner for reliable human
proximity detection as opposed to capacitive proximity sensing
technology which may require increased distance between the
multiple capacitive sensing electrodes and sensor integrated
circuits needed, leading to increased susceptibility to noise and
reduction in proximity detection performance.
[0007] In one embodiment, the disclosed systems and methods may be
implemented to control SAR resulting from multiple transmit
antennas of a single wireless-enabled information handling system
platform, including relatively small sized wireless platforms
having multiple transmit antennas. This capability is advantageous
given the current trend of increased number of transmit antennas
supported by a single wireless platform device coupled together
with the current trend of decreasing the typical physical wireless
device size, e.g., such that SAR conformance is also required for
Wi-Fi emissions. Examples of system platform types and environments
with which the disclosed systems and methods may be advantageously
implemented to meet FCC or other governmental agency SAR
requirements for RF signal exposure without significant degradation
of the wireless performance include, but are not limited to
handheld end user computing (EuC) systems such as tablet-first
designs.
[0008] In one exemplary embodiment, the disclosed systems and
methods may be implemented using multiple different types of
sensors provided on board an information handling system. In a
further embodiment, these different types of sensors may include
all the existing sensors that are provided in a
commercial-off-the-shelf (COTS) information handling system
platform to more intelligently control SAR emissions from the
platform. In any case, smart usage of various combinations of
multiple sensors may be implemented to increase proximity detection
field of view around an information handling system platform, and
may be further implemented to reduce or substantially eliminate
occurrence of false positive identification of a nearby human user
that requires SAR RF transmit power reduction.
[0009] In one embodiment, a fusion of multiple sensors of a
wireless-enabled information handling system platform may be used
to provide a more detailed system and environment view of the
device platform to enable intelligent and dynamic SAR control
configurations. For example, one exemplary embodiment of the
disclosed systems and methods may utilize knowledge of a wireless
device usage profile (e.g., stored in system memory) for a given
wireless information handling system to predict likelihood of SAR
trigger events for that given information handling system.
[0010] In another embodiment, the scope of SAR control may be
extended, e.g., by using one or more additional sensor/s or other
type devices that are located on some other (proximity adjacent)
objects rather than on the information handling system platform
itself to determine proximity of a human user to a mobile device
antennae of concern. Such off-platform devices may communicate with
processing devices of the information handling system, for example,
via wired or wireless communication (e.g., Bluetooth RF signal
communication, optical communication such as infrared signals, near
field communication signals, etc.). Examples of such other objects
include, but are not limited to, the body of the current use of the
information handling system (e.g., such as using a capacitive,
other type proximity sensor or short range RF transmitter located
on a user-wearable component that communicates proximity-indicative
signals to the system platform that may contain sensed proximity
distance values or that may have a received signal strength that
varies with proximity to the system platform), or a nearby notebook
computer (e.g., the nearby proximity of a human user's body to a
cellular phone system platform may be positively detected and
reported to processing device/s of the system platform when the
user generates input signals by typing on the keyboard of a
notebook computer that is wirelessly tethered via Bluetooth to the
cellular phone wireless device that is in turn transmitting via
Wireless Wide Area Network "WWAN" RF cellular signals).
[0011] Specific examples of different types of hardware and/or
methodology that may be employed in the practice of the disclosed
systems and methods for human proximity detection to detect nearby
proximity of a human body to a wireless-enabled information handing
system platform include, but are not limited to: 1) thermal sensors
such as thermocouples or resistance temperature detectors (RTDs) or
thermistors for thermal sensing (e.g., mapping variations in sensed
temperature due to contact of a user's human tissue with the
platform at different temperature); 2) motion detector to detect
motion (e.g., if a mobile information handling system platform has
been motionless for a certain period of time then it may be assumed
that the platform is not currently being held by a human being); 3)
display touch sensor (e.g., detecting a user holding a touch screen
display device by using edge touch detection to determine the
location of a user's hands and/or fingers when the user is holding
the mobile device, and if no touch activity has been reported from
the touch screen for a specified period of time and there is IP
traffic then it may be assumed that the touch screen display device
is not being held by a human--examples of such use cases include
Personal Hotspot, Music listening, Video watching, etc.); 4)
biometrics sensor (e.g., such as a sensor capable of detecting a
nearby user's heart beat and that is placed in proximity to the
wireless device platform transmit antennas of concern--such sensors
are conventionally employed in wearables and may provide a
relatively high level of certainty that an object detected is
indeed human tissue); 5) Local localization techniques (e.g., local
localization techniques may be established between a
wireless-enabled information handling system platform such as a
tablet or notebook computer and a second device that is physically
associated with a user (such as a user-wearable like a Watch) to
determine the real time distance between the user and the wireless
platform--in this case some wireless device platforms have
restricted access and usage to a certain very limited number of
users (such as one, two or more identified users). It will be
understood that in a further embodiment, any of such human
proximity detection schemes such as described above may be enhanced
by a Machine Learning engine, e.g., such as running on the wireless
information handling system platform based on user usage
history.
[0012] In one respect, disclosed herein is an information handling
system platform, including: multiple sensors that are each
configured to react to a proximity of a human user to the system
platform by producing a sensor output signal that is indicative of
a proximity distance of the human user to the system platform; one
or more antenna elements; at least one transmitter coupled to the
one or more antenna elements and configured to transmit radio
frequency (RF) signals from each of the antenna elements; and at
least one processing device coupled to the transmitter, the
processing device being coupled to receive the sensor output
signals of the multiple sensors and to determine a real time object
proximity detection distance from each of the multiple sensor
output signals. The at least one processing device of the system
platform may be further configured to control the transmitter to
reduce RF transmit power according to at least one proximity
distance sensing profile that defines a relationship between RF
transmit power reduction and the determined object proximity
detection distance according to the multiple sensor outputs.
[0013] In another respect, disclosed herein is a method of
operating an information handling system platform, including: using
multiple sensors of the information handling system platform to
detect a proximity of a human user to the system platform by
producing a sensor output signal that is indicative of a proximity
distance of the human user to the system platform; using at least
one processing device of the information handling system platform
to receive the sensor output signals of the multiple sensors and to
determine a real time object proximity detection distance from each
of the multiple sensor output signals; and using the at least one
processing device of the information handling system platform to
control a transmitter of the information handling system platform
to reduce RF transmit power from one or more antennas of the
information handling system platform according to at least one
proximity distance sensing profile that defines a relationship
between RF transmit power reduction and the determined object
proximity detection distance according to the multiple sensor
outputs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A illustrates a block diagram of a wireless-enabled
information handling system platform according to one exemplary
embodiment of the disclosed systems and methods.
[0015] FIG. 1B illustrates examples of multiple sensors for an
information handing system platform according to one exemplary
embodiment of the disclosed systems and methods.
[0016] FIG. 2 illustrates a block diagram of SAR control components
of an information handling system platform according one exemplary
embodiment of the disclosed systems and methods.
[0017] FIG. 3 illustrates a block diagram showing operational
aspects of SAR control logic components of an information handling
system platform according one exemplary embodiment of the disclosed
systems and methods.
[0018] FIG. 4 illustrates methodology according one exemplary
embodiment of the disclosed systems and methods.
[0019] FIG. 5 illustrates RF transmit power reduction for multiple
sensors as a function of human body proximity distance to an
information handling system platform according to one exemplary
embodiment of the disclosed systems and methods.
[0020] FIG. 6 illustrates a zone of uncertainty of RF transmit
power reduction for a given actual proximity detection distance
according to one exemplary embodiment of the disclosed systems and
methods.
[0021] FIG. 7 illustrates a fitted curve of RF transmit power
reduction as a function of actual human body proximity detection
distance according to one exemplary embodiment of the disclosed
systems and methods.
[0022] FIG. 8 illustrates ranges of RF transmit power reduction
levels assigned to different human body proximity detection
distance thresholds defined in a fitted curve for multiple
sensors.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0023] FIG. 1A illustrates a block diagram of a wireless-enabled
information handling system platform 100 that in this exemplary
embodiment is configured as a tablet computer. Although a tablet
computer is illustrated, it will be understood that the disclosed
systems and methods may be implemented with any other type of
wireless-enabled information handling system having integral or
on-board RF antenna/s including, for example, portable or mobile
information handling systems such as notebook computers, laptop
computers, smart phones, PDA's, etc.
[0024] Still referring to FIG. 1A, information handling system
platform 100 includes integrated RF antennas 102a and 102b, which
are each coupled to a transmitter that includes respective RF tuner
104a or 104b and radio front end 106 as shown. In the illustrated
embodiment, separate tuners 104a and 104b are configured to modify
the operating characteristics of the separate antenna elements 102a
and 102b, respectively, based on the operating state of the
baseband processor 108 and radio front end 106, e.g., based on the
current frequency band or RF channel in use. Circuitry of RF tuners
104 and radio front end 106 is configured to perform intermediate
frequency (IF) to RF up conversion mixing and RF processing tasks
for outgoing transmitted signals to antennas 102, and vice-versa
(including down conversion) for incoming received signals from
antennas 102. Besides IF, front end 106 may perform up conversion
and down conversion between RF and other suitable frequencies for
processing by baseband processing device or processor 108, e.g.,
such as zero-IF frequency, baseband frequency, etc. In this regard,
baseband processor 108 (e.g., digital signal processor "DSP" or
other suitable RF module or processing device/s) is coupled to
exchange outgoing and incoming IF or other suitable signals with
baseband processor 108 through respective digital-to-analog (DAC)
and analog-to-digital (ADC) converters (not shown). Baseband
processor 108 may be configured to manage RF signal transmission
and reception, as well as to perform tasks including signal
processing, encoding, frequency shifting and/or modulation
operations to provide transmitted information in outgoing signals
based on digital data provided by application processor 110, and to
perform signal processing, decoding, frequency shifting and/or
demodulation operations to obtain the message content in the
incoming signals as digital data to provide to application
processor 110.
[0025] Application processor 110 may in one embodiment be a host
processing device (e.g., such Intel or AMD-based central processing
unit "CPU") or other suitable type of processing device configured
to execute a host operating system (OS) and to exchange outgoing
and incoming and outgoing digital data with baseband processor 108.
Application processor 110 may be coupled as shown to main system
memory 111 (e.g., dynamic random access memory "DRAM" or other
suitable type of system memory), and to system storage 113 (e.g.,
media drive/s such as magnetic hard drive/s or optical storage
drive/s, solid state drive/s "SSD", other non-volatile memory
device/s, etc.). Such storage and memory devices may also be
accessible to other processing devices of system platform 100.
Application processor 110 may also be configured to execute an
operating system (OS) such as Microsoft Windows-based, Linux-based,
Apple OS-based or other suitable operating system, as well as to
execute applications and system BIOS for system platform 100. Among
other things application processor 110 may be coupled (e.g., via a
platform controller hub "PCH") to one or more I/O devices or
circuitry of system 100 including, but not limited to, video
display circuitry, touch-sensitive circuitry or touch pad or
keyboard for accepting user input, audio amplifier circuitry and
system speaker/s, system microphone, etc.
[0026] Further shown in FIG. 1A is sensor fusion hub with
co-processor 112 that is coupled to receive sensor inputs from
multiple sensors 120, detect nearby proximity of a human user from
the multiple sensor inputs, and to determine transmit power
reduction based on the multiple sensor inputs in a manner described
further herein. It will be understood that in one embodiment, a
co-processor 112 may be an integrated component provided within a
fusion hub as illustrated. In an alternative architecture
embodiment, a co-processor may be a dedicated processing device
component that is used instead of a fusion hub processing
component.
[0027] In one exemplary embodiment, co-processor 112 may be a
system-on-a-chip (SoC) that includes an Advanced RISC Machines
(ARM)-based processor, although any other suitable type of
co-processor or other type of processing device/s may be
alternatively employed. It is also possible that the operational
tasks of co-processor 112 may also be performed by an application
processor 110 or other type of single processor, or may be divided
or partitioned between multiple different processing devices of a
system 100. It will be understood that multiple sensors 120 coupled
to co-processor 112 may be any combination of different sensor
types that are configured or otherwise capable of detecting or
otherwise reacting to the nearby proximity of a human user to
system platform 100 by producing a sensor output signal that is
indicative of the nearby proximity of the human user.
[0028] FIG. 1B illustrates multiple on-platform sensors 120 that
may be coupled to provide sensor output signals to co-processor 112
of information handling system platform 100, with specific examples
of particular types of sensors 120 being listed in FIG. 1B. Each of
sensors 120 may be co-located or integral to system platform 100
and coupled internally to its other components, or may be
positioned external to system platform 100 and coupled to
components of system by suitable external I/O ports. FIG. 2
illustrates a block diagram of an exemplary embodiment of the SAR
control components of system platform 100, showing a more detailed
interrelation of example types of multiple sensors 120 with
co-processor 112 that each have different proximity detection
distance threshold characteristics. As shown in FIG. 2, suitable
sensors 120 may include, but are not limited to, camera/s 120a,
motion sensor/s 120b, light sensor/s 120c, environment/health
sensor/s 120d, acoustic sensor/s 120e, infrared (IR) sensor/s 120f
(such as IR camera/s), capacitive proximity sensor/s 120g, and
fingerprint sensor/s 120h. It will be understood that this list of
possible sensor types is not exhaustive, and that other additional
or alternative sensor types may be operatively employed in a system
platform 100. Moreover, not all of the types of sensors 120
illustrated in FIG. 1B need be present, and/or two or more a given
type of sensor 120 may be operatively employed in a given system
platform 100.
[0029] FIG. 1B also illustrates optional off-platform devices 155
that may be located on some other (proximity adjacent) objects
rather than on the information handling system platform 100 itself,
but nonetheless used by information handling system 100 to
determine proximity of a human user to a mobile device antennae 120
of concern. Such off-platform devices 155 may communicate with
processing devices of the information handling system platform 100,
for example, via wired or wireless communication (e.g., Bluetooth
RF signal communication, optical communication such as infrared
signals, near field communication signals, etc.). Examples include,
but are not limited to, a capacitive, other type proximity sensor
or short range RF transmitter located on a user-wearable component
157 that communicates proximity-indicative wireless signals to the
system platform that may contain sensed proximity distance
information itself or that may be received by information handling
system 100 with a received signal strength that varies according to
the proximity to the system platform 100); or a nearby notebook
computer 159 having a keyboard that may be used to detect the
nearby proximity of a human user's body to information handling
system platform 100 when it is tethered nearby to notebook computer
159 by wirelessly reporting user typing activity on the keyboard of
a notebook computer to processing device/s of the system platform
100 when the user generates input signals by typing on the keyboard
of a notebook computer 159.
[0030] As shown in FIG. 2, co-processor 112 (e.g. integrated within
a sensor fusion hub such as illustrated in FIG. 2) may be
configured to contain a proximity-sensing engine that acts as the
proximity-sensing brain of the fusion hub. In this embodiment, the
proximity-sensing engine may be the core logic that is configured
to perform operations to process a proximity sensing algorithm 210.
In this regard the proximity-sensing engine may be configured to
execute the proximity sensor algorithm 210 (e.g., as a proximity
sensing library and application programming interface "API"), issue
commands and receive interrupts from the array of sensors 120 that
are used for measuring proximity of nearby human users, and to
produce a SAR power control command 260 that is provided through
application processor 110 to baseband processor 108 as shown.
Baseband processor 108 is in turn configured to execute dynamic
power reduction control logic 220 that is configured to receive the
SAR power control command 260 and based thereon to produce a SAR
power level control signal 270 that is provided to circuitry of RF
tuners 104 and radio front end 106 to control the RF transmission
power level for RF signals transmitted from antenna 102 at any
given time.
[0031] FIG. 3 illustrates a block diagram showing operational
aspects of the various SAR control logic components of system
platform 100. As shown in FIG. 3, application processor 110 is
configured to execute a connectivity application which operates to
cause uploading or downloading of data via RF signals received and
transmitted by antenna 102 to a wireless network through baseband
processor 108 and RF tuner and radio front end components of
transmitter 104/106 in a manner as previously described.
Connectivity application 110 may be any application (e.g.,
software, firmware, etc.) that executes to upload or download data
to wireless network, for example, an Internet browser application,
email application, software update application, etc. As further
shown in FIG. 3, proximity sensor algorithm 210 is configured to
execute as programmed logic on co-processor 112, and is coupled to
receive signals from connectivity application 110 that makes usage
context manager component logic 302 of proximity sensor algorithm
210 aware of the current data transfer status (e.g., data uploading
or data downloading operation for a given type of RF band and
antenna 102) being performed by connectivity application 110. Usage
context manager component 302 in turn sets a transmit or receive
usage context mode identifier 304 that indicates whether a RF
transmission operation or reception operation is currently taking
place on a given RF band on a given antenna/s 102. It will be
understood that the transmit or receive usage context mode
identifier 304 may be further mapped and modified according to
other aspects of the device usage, e.g., such as the device
orientation of system platform 100.
[0032] As shown in FIG. 3, multiple proximity distance sensing
profiles 306 may be retrieved by proximity sensor algorithm 210
from storage in non-volatile memory (e.g., NVRAM) of co-processor
112, or from any other suitable memory device accessible by
co-processor 112. In one embodiment each proximity sensing profile
306 may be defined based on a given radio transmit antenna 102
currently being used, with different profiles 306 applying to
different respective antennas 102. Each proximity sensing profile
306 may in turn define a relationship between RF transmit power
reduction (e.g., as a percentage or fraction of maximum possible
power transmission, as an offset from maximum power transmission
wattage level, etc.) and determined nearby object proximity
detection distance according to sensor outputs received as inputs
by sensor fusion and calibration logic 310 of proximity sensor
algorithm 210 from multiple system sensors 120, e.g., sensors
120a-120h. In one embodiment, proximity sensor algorithm 210 may in
turn dynamically communicate SAR power control commands 260 to
baseband processor 108. SAR power control commands 260 may be in
the form of smart sensing fused sensor profile parameter values
determined (e.g., for a given antenna or antennas 102) from a
combination of fused sensor information (from sensor fusion and
calibration logic 310) and proximity distance sensing profiles
306.
[0033] SAR power control commands 260 transmitted from proximity
sensor algorithm 210 cause dynamic power reduction control logic
220 of baseband processor 108 to produce and provide a
corresponding SAR power level control signal 270 to RF tuners
104/radio front end 106 so as to implement usage context-based and
proximity detection-based power reduction and to secure optimized
performance while at the same time meeting SAR RF exposure
requirements. RF tuners 104/radio front end 106 are in turn
configured to control RF transmission power level to a given
antenna antennas 102 according to SAR power level control signal
270 provided for the given antenna/s 102. In this manner, smart
usage of various combinations of multiple sensors 120 may be
employed to increase proximity detection field of view and
elimination of false positives with respect to nearby human user
detection.
[0034] As further shown in FIG. 3, proximity sensor algorithm 210
may also be optionally configured to receive usage and environment
change inputs 320 for system platform 100, e.g., inputs such as
provided from primary or secondary device usage modes as may be
configured on the system platform device by a user. Examples of
different such usage modes include, but are not limited to, tablet
usage mode and notebook usage mode (e.g., in tablet usage mode the
display orientation of system platform 100 may be either landscape
or portrait orientation depending on current running application
and/or on current physical orientation of the system platform 100,
while in notebook mode the display orientation may be fixed to be
only landscape mode orientation), etc. Examples of such usage and
environment change inputs 320 include, but are not limited to,
information on environment and operational condition and/or mode
changes (such as changes between convertible computer portable mode
to stand mode and vice-versa, changes between portrait and
landscape orientation for tablet computer system platform, etc.)
Multiple different proximity sensing profiles 306 may in turn be
defined that each correspond to a different one of multiple
possible usage and/or environment modes and/or conditions.
Proximity sensor algorithm logic 210 may optionally consider one or
more usage and environment change input/s 320 together with fused
sensor information to determine smart sensing fused sensor profile
parameter values from proximity distance sensing profiles 306.
[0035] In one exemplary embodiment, how a system platform is
configured and used may be a primary input in determining the
proximity distance profiles 306. For example, if the system
platform is configured as a hybrid/2-in-1/detachable device it may
be configured in several ways by a user. In some usage modes (such
as notebook open mode or notebook closed mode) then the proximity
sensing function may be disabled or put in a sleep state by
proximity sensor algorithm 210. However, if the system platform is
configured (or reconfigured) in tablet mode by the user, it may be
used in a number of orientations such as primary landscape, primary
portrait, secondary landscape or secondary portrait. In each of
these orientations proximity sensing be enabled by proximity sensor
algorithm 210, and may require separate proximity distance profiles
306 depending on the location of the sensors 120 and transmitting
antennae 102 in the system
[0036] Also shown in FIG. 3 is resource management logic 308 that
may be executed as part of proximity sensing algorithm 210 by
co-processor 112 to select among multiple sensor inputs 120 for
purposes of managing and monitoring the resources required for the
sensors 120, such as the number and type of interfaces required,
interrupt handling and sensor data buffering requirements etc.
[0037] As will be further described herein in relation to FIGS.
5-8, individual proximity distance profiles 306 may be associated
with each transmit antenna 102 and/or sensor 120 of FIG. 2 based on
upper and lower detection thresholds that are configurable by the
proximity sensing engine of co-processor 112. As previously
mentioned, each of the multiple types of sensors of FIG. 2 may have
different coarseness of proximity detection distance threshold. For
example, camera sensor/s 120a may have the most coarse proximity
detection distance threshold, motion sensor/s 120b (e.g.,
accelerometer, gyroscope, etc.) may have a relatively finer
proximity detection distance threshold than camera/s 120a,
touch/gesture (e.g., user hand-gesture) sensor/s 120c may have a
relatively finer proximity detection distance threshold than motion
sensor/s 120b, barometric pressure sensor/s 120d may have a
relatively finer proximity detection distance threshold than
touch/gesture sensor/s 120c, acoustic sensor/s 120e may have a
relatively finer proximity detection distance threshold than
pressure sensor/s 120d, IR sensor/s 120f may have a relatively
closer proximity detection distance threshold than acoustic
sensor/s 120e, capacitive proximity sensor/s 120g may have a
relatively finer proximity detection distance threshold than IR
sensor/s 120f, and fingerprint sensor/s 120h may have a relatively
finer proximity detection distance threshold than capacitive
sensor/s 120g. As previously mentioned, the particular types and
number of different sensors 120 of FIG. 2 are exemplary only, and
any combination of fewer, additional, and/or alternative different
types of sensors 120 may be provided for a given configuration of
an information handling system platform 100.
[0038] In one exemplary embodiment, individual sensor proximity
distance sensing profiles 306 may be calibrated for each of the
sensors 120 used for detection, e.g., using sensor fusion and
calibration logic 310. The proximity distances in each profile 306
may be updated by the proximity sensing engine of co-processor 112
to compensate for environmental drift. In this regard, some sensors
120 may be subject to environmental drift (bias) that introduces
errors and deviation from the original sensor calibrated levels.
Such sensor drift of individual sensors 120 may cause changes in
the proximity distance sensing profiles 306 and thus require
compensation to correct for these errors. Sensor fusion and
calibration logic 310 may be configured to implement automatic
sensor calibration algorithms to address drift via frequent
self-recalibration.
[0039] FIG. 4 illustrates one exemplary embodiment of methodology
400 that may be employed to utilize multiple sensors 120 to
intelligently control SAR produced from a wireless-enabled
information handling system platform 100. As shown, methodology 400
begins in step 402 where each of multiple sensors 120 of a
particular configuration of information handling platform 100 is
characterized for human body proximity detection distance
(representing the actual distance of the closest part of a human
body the information handling system platform) and corresponding RF
transmit power reduction. This characterization may be performed in
one embodiment using empirical measurements on an actual
information handling system platform device 100 during development
or manufacture of the information handling system platform 100,
e.g., such as in a development lab. Measurement characterization of
step 402 may be performed for all main usage modes (e.g., such as
tablet primary landscape and portrait modes) and radio transmit
antennas 102, e.g., such as antennas 102a and 102b of FIG. 1A. In
one embodiment, characterization of step 402 may be performed for
information handling system platform device 100 and corresponding
antennas 102a and 102b that are configured for transmission of WWAN
RF signals (e.g., LTE, WiMAX or wireless metropolitan area network
"WMAN", GSM, cellular digital packet data (CDPD), universal mobile
telecommunications system (UMTS), CDMA2000, Mobitex, etc. signals),
and/or Wi-Fi RF signals (e.g., 2.4 GHz and/or 5 GHz 802.11x
standards-based signals, etc.).
[0040] FIG. 5 illustrates an example of such characterization of
each of multiple sensors 120a-120g of the information handling
system platform device of FIG. 2 for human body proximity detection
distance (i.e., increasing distance in millimeters, centimeters,
inches or other suitable measurement unit occurring from left to
right on X-axis) and corresponding RF transmit power reduction
(i.e., increasing percentage reduction in maximum transmit power
occurring in upward direction on Y-axis) for one of antennas 120
operating in a given usage mode to meet SAR requirements, e.g., as
specified by FCC 941225 D01 SAR testing procedure for 3G devices,
FCC 941225 D05 SAR testing procedure for LTE Devices, FCC 941225
D06 SAR testing procedure for hotspot devices, FCC 941225 D07 UMPC
testing procedures for mini tablet devices, etc.
[0041] As illustrated in FIG. 5, each of different sensors
120a-120g has a different individual sensor proximity distance
sensing profile 306 that in this embodiment includes an individual
sensor curve, and that has a different effective range of human
body proximity detection distance, detection sensitivity, and
corresponding indicated RF transmit power reduction amount for a
given value of actual proximity distance of a human body to
information handling system platform 100 that is indicated by
X-axis value of FIG. 5. In this regard, each of sensors 120 may be
configured to produce a sensor output signal that varies with
different proximity distance of a human body to the system platform
100 (e.g., such as varying capacitance signal value, varying sound
level signal value, varying barometric pressure level signal value
level, varying motion level signal value, varying light level
signal value, etc.). Further, as shown in FIG. 5 each of sensors
120 may be assigned (e.g., based on empirical SAR compliance
measurement for a corresponding transmitter during laboratory
testing, or other suitable testing methodology) a varying indicated
RF transmit power reduction amount that varies as a function of
different proximity distances of a human body to the system
platform 100 based on the varying value of its respective sensor
output signal as the actual proximity distance of a human body to
the system platform 100 (X-axis value) changes.
[0042] FIG. 5 also illustrates that for the particular range of
detection distances corresponding to dashed box 500 of FIG. 5, a
different amount of RF transmit power reduction is indicated by the
overlap of the individual sensor curves of proximity distance
sensing profiles 306 for different sensors 120d and 120e for the
same range of actual detected human body proximity distances, i.e.,
with sensor 120d indicating a larger reduction in RF transmit power
than sensor 120e for the same given value of determined actual
proximity distance of a human body to information handling system
platform 100 that falls within box 500. Thus, more than one RF
transmit power reduction value is indicated for a given actual
distance determined from multiple overlapping sensors. This creates
a zone of uncertainty 600 of required RF transmit power reduction
for a given actual proximity detection distance as illustrated in
FIG. 6, for which an optimal RF transmit power reduction to meet
SAR requirements may be further determined as further described
herein. Fingerprint sensor 120h of FIG. 2 is not included in the
characterization of FIG. 5 since it positively identifies proximity
of a human finger touching information handling system platform 100
at a known distance for which a fixed and known SAR RF transmit
power reduction value may be assigned.
[0043] Still referring to FIG. 4, a blended relationship in the
form of a fitted curve 700 of RF transmit power reduction as a
function of actual human body proximity detection distance over the
multiple sensors 120a-120g may be created (e.g., in real time by
proximity sensor algorithm 210) in step 404 for each antenna 102
and/or usage mode as illustrated in FIG. 7. In this step, a blended
multi-sensor curve fitting approach may be employed to smooth RF
transmit power reduction steps over human body (e.g., human hand)
proximity detection distances for each antenna 102 and/or usage
mode. Fitted curve 700 may be determined using any suitable
curve-fitting methodology from the individual RF transmit power
reduction value profiles of the corresponding individual sensors
120, e.g., such as a least squares method, total least squares
method, interpolation between two consecutive sensor curves of FIG.
7 in the decreasing detection distance direction (i.e., in the
right to left direction along X-axis of FIG. 7), interpolation
between two consecutives curves of FIG. 7 in the increasing
detection distance direction (i.e., in the left to right direction
along X-axis of FIG. 7), etc. It will be understood that in other
embodiments any other suitable type of blended relationship of
different RF transmit power reduction values derived from different
sensors as a function of proximity detection distance from the
multiple sensors having different effective object distance
detection ranges may be employed, e.g., such as a lookup table of
blended power reduction values that are each calculated from the
average RF transmit power reduction values for two or three sensors
having adjacent effective object distance detection ranges.
[0044] FIG. 8 illustrates the resulting ranges of RF transmit power
reduction levels assigned to different human body proximity
detection distance thresholds defined in the fitted curve 700 for
the multiple sensors 120a-120g as illustrated by the bracketed
X-axis detection distance ranges of FIG. 8. Each of these different
human body proximity detection distance thresholds (together with
corresponding X-axis bracketed distance ranges defined between
these distance thresholds) of fitted curve 700 corresponds to only
a given one of sensors 120, and is to be used one at a time when
the corresponding proximity distance detected by the given sensor
falls within its corresponding distance range (i.e., so as to "hand
off" RF transmit power reduction control between different
successive sensors 120 as detection distance changes according to
the indicated distance thresholds and corresponding bracketed
X-axis detection distance ranges). It will be understood that the
number and type of sensors 120 illustrated in FIGS. 7 and 8 are
exemplary only, and that it is possible to selectively implement
the proximity sensor algorithm 210 to utilize any specified subset
of all the available sensors on a system platform, e.g., in real
time or by pre-defined default selection.
[0045] For example, RF transmit power reduction range 800 (P2)
defined by fitted curve 700 is specified for the bracketed X-axis
detection distance range assigned only to sensor 102f between
sensor brackets 102e and 102g as shown, with similar RF transmit
power reduction ranges being individually specified for (and
assigned to) each individual sensor 120 as indicated by the
different bracketed detection distance ranges of the X-axis
proximity detection distance denoted for each sensor 120 in FIG. 8.
Thus when the determined detection distance values measured by
sensor 102f fall within the assigned bracketed X-axis distance
value range 102f of FIG. 8, a corresponding RF transmit power
reduction range 800 (P2) is indicated and defined by curve 700. It
will also be understood that each different antenna 102 and/or
usage mode may be assigned a different shaped curve 700 that
corresponds to the required SAR transmit power reduction, and that
each transmit antenna 102 and/or usage mode may be assigned such a
curve as a proximity distance sensing profile 306 described
previously in relation to FIG. 3.
[0046] Next, in step 406, proximity sensor algorithm 210 may be
configured with the fitted proximity distance sensing profiles 306
for use by the proximity sensing library and API, which is
configured to take inputs from all of multiple sensors 120a-120g
and to deliver corresponding smart sensing fused profile parameters
corresponding to a given transmit antenna 102 to baseband radio
processor 108 (or to each baseband radio processor 108 for system
platforms 100 having multiple baseband radio processors 108). In
step 408, each baseband radio processor 108 is configured to
register with and accept the smart sensing fused sensor profile
parameters as input from proximity sensor algorithm 210, and to use
the smart sensing fused sensor profile parameters to control and
optimize output power for the given transmit antenna 102.
[0047] Next, in step 410, smart sensing fused sensor profile
parameter values 260 for a given antenna 102 and/or usage mode that
are based on sensor inputs received from sensors 102a-102g are
delivered by proximity sensor algorithm 210 to baseband radio
processor 108. In this regard, a radio driver in baseband processor
108 is configured to register with proximity sensing API of
proximity sensor algorithm 210 to receive these smart sensing fused
sensor profile parameter values 260. In step 412, dynamic power
reduction control logic 220 of baseband radio processor 108 is
configured to dynamically configure output power reduction (e.g.,
as a selected fraction of full transmit output power) by using the
received smart sensing fused sensor profile parameter values 260
together with radio and antenna operating parameters as inputs for
performance optimization for SAR RF power reduction during transmit
usage mode determined by usage context manager 302 for a given
antenna 102. In this regard, such radio and antenna operating
parameters used in step 412 may be, for example, the identity of
the frequency band or frequency channel in use by the baseband
processor 108 and radio front end 106, and/or the tunable antenna
band switching or impedance matching state, etc. In one embodiments
such radio and antenna operating parameters may alter to a greater
or lesser degree the amount of power reduction that is applied for
SAR performance.
[0048] In step 414, dynamic power reduction control logic 220 of
baseband radio processor 108 delivers the dynamic power adjustment
as control signals 270 to the respective radio transmit chain
(e.g., radio front end 106 and tuner 104) and given antenna 102. In
this way, closed-loop optimization of SAR RF power reduction
performance for each proximity event detection distance, usage
mode, radio operating condition, and transit antenna 102 may be
achieved. In step 416, proximity sensor algorithm 210 monitors for
changes in proximity event detection distance, usage mode, radio
operating condition, and/or transit antenna 102, and repeats to
step 410 as shown.
[0049] It will be understood that the illustrated steps of
methodology 400 are exemplary only, and that any other combination
of additional, fewer and/or alternative steps may be employed that
is suitable to implement utilize multiple sensors to intelligently
control SAR produced from a wireless-enabled information handling
system platform in the presence of a detected nearby human body. It
will also be understood that the steps of methodology 400 may be
implemented with configurations of RF transmission capable
information handling system platform configurations other than that
illustrated in relation to FIGS. 1-3. Such alternative
configurations include information handling system platforms that
include only one transmit antenna 102, that include multiple
transmit antennas 102 and multiple baseband processors 108 (with
corresponding radio transmit chains), etc.
[0050] It will also be understood that one or more of the tasks,
functions, or methodologies described herein (e.g., including those
described herein for components 108, 110, 112, etc.) may be
implemented by circuitry and/or by a computer program of
instructions (e.g., computer readable code such as firmware code or
software code) embodied in a non-transitory tangible computer
readable medium (e.g., optical disk, magnetic disk, non-volatile
memory device, etc.), in which the computer program comprising
instructions are configured when executed (e.g., executed on a
processing device of an information handling system such as CPU,
controller, microcontroller, processor, microprocessor, FPGA, ASIC,
or other suitable processing device) to perform one or more steps
of the methodologies disclosed herein. A computer program of
instructions may be stored in or on the non-transitory
computer-readable medium accessible by an information handling
system for instructing the information handling system to execute
the computer program of instructions. The computer program of
instructions may include an ordered listing of executable
instructions for implementing logical functions in the information
handling system. The executable instructions may comprise a
plurality of code segments operable to instruct the information
handling system to perform the methodology disclosed herein. It
will also be understood that one or more steps of the present
methodologies may be employed in one or more code segments of the
computer program. For example, a code segment executed by the
information handling system may include one or more steps of the
disclosed methodologies.
[0051] For purposes of this disclosure, an information handling
system may include any instrumentality or aggregate of
instrumentalities operable to compute, classify, process, transmit,
receive, retrieve, originate, switch, store, display, manifest,
detect, record, reproduce, handle, or utilize any form of
information, intelligence, or data for business, scientific,
control, entertainment, or other purposes. For example, an
information handling system may be a personal computer, a PDA, a
consumer electronic device, a network storage device, or any other
suitable device and may vary in size, shape, performance,
functionality, and price. The information handling system may
include memory, one or more processing resources such as a central
processing unit (CPU) or hardware or software control logic.
Additional components of the information handling system may
include one or more storage devices, one or more communications
ports for communicating with external devices as well as various
input and output (I/O) devices, such as a keyboard, a mouse, and a
video display. The information handling system may also include one
or more buses operable to transmit communications between the
various hardware components.
[0052] While the invention may be adaptable to various
modifications and alternative forms, specific embodiments have been
shown by way of example and described herein. However, it should be
understood that the invention is not intended to be limited to the
particular forms disclosed. Rather, the invention is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the invention as defined by the appended
claims. Moreover, the different aspects of the disclosed systems
and methods may be utilized in various combinations and/or
independently. Thus the invention is not limited to only those
combinations shown herein, but rather may include other
combinations.
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