U.S. patent application number 14/275887 was filed with the patent office on 2014-11-13 for adjustment of radiation patterns utilizing a position sensor.
This patent application is currently assigned to Ruckus Wireless, Inc.. The applicant listed for this patent is Ruckus Wireless, Inc.. Invention is credited to Bernard Baron, William S. Kish, Victor Shtrom.
Application Number | 20140334322 14/275887 |
Document ID | / |
Family ID | 42224160 |
Filed Date | 2014-11-13 |
United States Patent
Application |
20140334322 |
Kind Code |
A1 |
Shtrom; Victor ; et
al. |
November 13, 2014 |
ADJUSTMENT OF RADIATION PATTERNS UTILIZING A POSITION SENSOR
Abstract
A device for a wireless RF link to a remote receiving device can
radiate at different radiation patterns in response to detecting a
change in the device position. As the device is moved, displaced,
or re-positioned, a position sensor in the device detects the
change in position and provides position information to a
processor. The processor receives the position information from the
position sensor, selects an antenna configuration and physical data
rate based on the position information, and provides an RF signal
associated with the selected antenna configuration through the
antenna elements of the selected antenna configuration.
Inventors: |
Shtrom; Victor; (Los Altos,
CA) ; Baron; Bernard; (Mountain View, CA) ;
Kish; William S.; (Saratoga, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ruckus Wireless, Inc. |
Sunnyvale |
CA |
US |
|
|
Assignee: |
Ruckus Wireless, Inc.
Sunnyvale
CA
|
Family ID: |
42224160 |
Appl. No.: |
14/275887 |
Filed: |
May 13, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13485012 |
May 31, 2012 |
8723741 |
|
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14275887 |
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|
12404127 |
Mar 13, 2009 |
8217843 |
|
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13485012 |
|
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Current U.S.
Class: |
370/252 |
Current CPC
Class: |
H01Q 3/24 20130101; H04L
1/0002 20130101; H04W 24/02 20130101; H04L 1/20 20130101; H04W
72/0413 20130101; H01Q 1/2291 20130101; H04B 7/063 20130101; H04W
84/12 20130101 |
Class at
Publication: |
370/252 |
International
Class: |
H04L 1/00 20060101
H04L001/00; H04B 7/06 20060101 H04B007/06; H04L 1/20 20060101
H04L001/20 |
Claims
1. A method for processing feedback at a wireless device, the
method comprising: computing a respective transmission success
ratio based on attempted transmissions of a data packet to a remote
receiving node for a plurality of antenna configurations of a
wireless device in a first position, wherein each of the plurality
of antenna configurations is associated with a different radiation
pattern; ranking the plurality of antenna configurations of the
wireless device in the first position based on the respective
computed transmission success ratios; determining a respective user
data rate for each physical data rate of each of the plurality of
antenna configurations of the wireless device in the first
position; ranking each physical data rate of each of the plurality
of antenna configurations of the wireless device in the first
position based on the determined respective user data rates;
selecting an antenna configuration from the plurality of antenna
configurations based on the rankings of the plurality of antenna
configurations for the wireless device in the first position; and
selecting a physical data rate based on the physical data rate
rankings and the selected antenna configuration of the wireless
device in the first position.
2. The method of claim 1, wherein the method further comprises:
detecting a first position of the wireless device using a tilt
sensor.
3. The method of claim 1, wherein the method further comprises:
detecting a first position of the wireless device using an
accelerometer.
4. The method of claim 1, wherein the method further comprises:
determining a respective received signal strength for each of the
plurality of antenna configurations.
5. The method of claim 4, wherein the method further comprises:
ranking the plurality of antenna configurations based on the
determined received signal strengths.
6. The method of claim 5, wherein selecting an antenna
configuration of the plurality of antenna configurations is based
on the received signal strength ranking.
7. The method of claim 1, wherein the method further comprises:
detecting a second position of the wireless device, wherein the
second position is different than the first position.
8. The method of claim 7, wherein the method further comprises:
computing respective transmission success ratios for the plurality
of antenna configurations of the wireless device in the second
position; ranking the plurality of antenna configurations of the
wireless device in the second position based on the computed
transmission success ratios; and selecting an antenna configuration
from the plurality of antenna configurations based on the
ranking.
9. The method of claim 8, wherein the method further comprises:
determining a respective user data rate for each physical data rate
of each of the plurality of antenna configurations of the wireless
device in the second position; ranking each physical data rate of
each of the plurality of antenna configurations of the wireless
device in the second position based on the determined respective
user data rates; and selecting a physical data rate based on the
ranking.
10. A wireless device for wirelessly exchanging data in a wireless
local area network, the wireless device comprising: an antenna
apparatus associated with a plurality of antenna configurations,
each antenna configuration associated with a different radiation
pattern; a position sensor that detects a first position of the
wireless device; a memory; and a processor that executes: a
feedback module stored in memory, wherein execution of the feedback
module includes: computing a respective transmission success ratio
based on attempted transmissions of a data packet to a remote
receiving node for a plurality of antenna configurations of a
wireless device in a first position, wherein each of the plurality
of antenna configurations is associated with a different radiation
pattern, ranking the plurality of antenna configurations of the
wireless device in the first position based on the respective
computed transmission success ratios, determining a respective user
data rate for each physical data rate of each of the plurality of
antenna configurations of the wireless device in the first
position, and ranking each physical data rate of each of the
plurality of antenna configurations of the wireless device in the
first position based on the determined respective user data rates;
an antenna configuration selection module stored in the memory, the
antenna configuration selection module selecting an antenna
configuration from the plurality of antenna configurations for the
antenna apparatus based on the ranking of the plurality of antenna
configurations; and a transmission control selection module stored
in the memory, the transmission control selection module selecting
a physical data rate based on the physical data rate rankings and
the selected antenna configuration of the wireless device in the
first position.
11. The wireless device of claim 10, wherein position sensor is a
tilt sensor.
12. The wireless device of claim 10, wherein position sensor is an
accelerometer.
13. The wireless device of claim 10, wherein execution of the
feedback module further includes: determining a respective received
signal strength for each of the plurality of antenna
configurations.
14. The wireless device of claim 13, wherein execution of the
feedback module further includes: ranking the plurality of antenna
configurations based on the determined received signal
strengths.
15. The wireless device of claim 14, wherein execution of the
antenna configuration selection module further includes selecting
an antenna configuration from the plurality of antenna
configurations based on the received signal strength ranking.
16. The wireless device of claim 10, wherein the position sensor
detects a second position of the wireless device, wherein the
second position is different than the first position.
17. The wireless device of claim 16, wherein: execution of the
feedback module further includes: computing respective transmission
success ratios for the plurality of antenna configurations of the
wireless device in the second position, and ranking the plurality
of antenna configurations of the wireless device in the second
position based on the computed transmission success ratios; and
wherein execution of the antenna configuration selection module
further includes: selecting an antenna configuration from the
plurality of antenna configurations based on the ranking.
18. The wireless device of claim 17, wherein: execution of the
feedback module further includes: determining a respective user
data rate for each physical data rate of each of the plurality of
antenna configurations of the wireless device in the second
position, and ranking each physical data rate of each of the
plurality of antenna configurations of the wireless device in the
second position based on the determined respective user data rates;
and wherein execution of the antenna configuration selection module
further includes: selecting a physical data rate based on the
ranking.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention is a continuation and claims priority
benefit to U.S. patent application Ser. No. 13/485,012 filed May
31, 2012, now U.S. Pat. No. 8,723,741, which is a continuation and
claims the priority benefit of U.S. patent application Ser. No.
12/404,127 filed Mar. 13, 2009, now U.S. Pat. No. 8,217,843, the
entirety of which is incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to wireless
communications and more particularly to changing radio frequency
(RF) emission patterns with respect to one or more antenna
arrays.
[0004] 2. Description of the Related Art
[0005] In wireless communications systems, there is an
ever-increasing demand for higher data throughput and a
corresponding drive to reduce interference that can disrupt data
communications. A wireless link in an Institute of Electrical and
Electronic Engineers (IEEE) 802.11 network may be susceptible to
interference from other access points and stations, other radio
transmitting devices, and changes or disturbances in the wireless
link environment between an access point and remote receiving node.
The interference may degrade the wireless link thereby forcing
communication at a lower data rate. The interference may, in some
instances, be sufficiently strong as to disrupt the wireless link
altogether.
[0006] One solution is to utilize a diversity antenna scheme. In
such a solution, a data source and intermediate RF generating
device are coupled to two or more physically separated
omnidirectional antennas. An access point may select one of the
omnidirectional antennas by which to maintain a wireless link.
Because of the separation between the omnidirectional antennas,
each antenna experiences a different signal environment and
corresponding interference level with respect to the wireless link.
A switching network couples the intermediate RF generating device
and corresponding data source to whichever of the omnidirectional
antennas experiences the least interference in the wireless
link.
[0007] Many methods that provide for switching among antenna
configurations, such as diversity antennas, and other methods of
controlling antenna segments fail to effectively minimize the
interference from other access points, other radio transmitting
devices, or disturbances in the environment of the wireless link
between the access point and the remote receiving node. Methods for
antenna configuration selection are typically by
trial-and-error.
[0008] In such a trial-and-error approach, a transmission is made
on each antenna configuration to determine which antenna
configuration provides a more effective wireless link as might be
measured by a packet error ratio. The trial-and-error approach is
inefficient as it generally requires transmission on a "bad"
antenna configuration to determine the particularities of the poor
quality of that antenna configuration. Further, as the transmitting
or receiving device move around, new sources of interference arise
to degrade a transmission. The trial-and-error approach therefore
becomes increasingly inefficient with a large number of antenna
configurations and devices that may have adjustable positions.
[0009] FIG. 1 is a block diagram of a wireless device 110 in
communication with one or more remote recipient device and as is
generally known in the prior art. While not shown, the wireless
device 110 of FIG. 1 includes an antenna apparatus, an RF
transmitter and/or a receiver, which may operate using the 802.11
protocol. The wireless device 110 of FIG. 1 may be illustrative of
a set-top box, a laptop computer, a television, a PCMCIA card, a
remote control, a cellular telephone, a handheld gaming device, or
a remote terminal.
[0010] The wireless device 110 may be a handheld device that
receives input through an input mechanism configured to be used by
a user. The wireless device 110 may then process the input and
generates an RF signal. The generated RF signal may then be
transmitted to one or more nodes 120, 130 and 140 via wireless
links. Nodes 120-140 may receive data, transmit data, or transmit
and receive data (i.e., a data transceiver).
[0011] Wireless device 110 may also be an access point for
communicating with one or more remote receiving nodes over a
wireless link as might occur in an 802.11 wireless network. The
wireless device 110 may receive data from a router connected to the
Internet (not shown). The wireless device 110 may then convert and
wirelessly transmit the data to one or more remote receiving nodes
(e.g., receiving nodes 120-140). The wireless device 110/access
point may also receive a wireless transmission from one of the
nodes 120-140 convert the data and allow for transmission of that
data over the Internet via the aforementioned router. The wireless
device 110 may also form a part of a wireless local area network
(LAN) that allows for communications among two or more of nodes
120-140. For example, node 140, which may be a cellular phone with
WiFi capability, may communicate with node 120, which may be a
laptop computer including a WiFi card or chip with wireless
capabilities. Those communications may be routed through the
wireless device 110, which creates the wireless LAN
environment.
[0012] Wireless device 110 may be placed in different positions on
a wall, desk, or in conjunction with another structure. The
radiation pattern emitted by the wireless device 110 may then be
based on the detected position of the device. A radiation pattern
that extends in a horizontal manner from the wireless device 110
may be desirable for a device mounted flat against a ceiling of
room or on a central table-like surface. Alternatively, when the
device is mounted on its side and against a wall, a radiation
pattern may extend outward in a vertical manner from the wireless
device 110. Such an arrangement may be desirable if one or more
nodes 120-140 are attempting to interact with an access point
(wireless device 110) on different floors of a building.
[0013] Arranging wireless access points or other wireless devices
in such a manner may require the party responsible for installation
of wireless device 110 to ensure that it is properly configured for
a horizontal and/or vertical wireless transmission. This is
especially true with prior art wireless devices and access points
that tend to transmit only in one-dimension. The particulars of any
given radiation pattern generated by a wireless device may be not
be immediately apparent to an individual charged with creating a
wireless network but otherwise lacking extensive knowledge into RF
emission patterns. Further difficulties might arise with respect to
intermediate arrangements of the wireless device (e.g., at a 45
degree angle).
[0014] The problems associated with radiation patterns become even
more apparent with respect to mobile devices, especially cellular
phones or mobile devices with WiFi capability. Such devices are
constantly in motion and may at one moment be on a horizontal plane
with an access point and a few moments later be vertical to the
access point. The angle of a mobile device vis-a-vis the access
point may change in as a little as a few seconds as a user may walk
around an office or even bring the device from their desktop up to
their ear as they stand at their desk.
[0015] There is a need in the art for adjusting antenna patterns
and corresponding radiation patterns to address the particularities
of any given wireless environment. Such a solution should take into
account not only causes of interference but also the physical
position and configuration of the transmitting or receiving
device.
SUMMARY OF THE PRESENTLY CLAIMED INVENTION
[0016] In a first claimed embodiment, a device for transmitting a
radiation signal is disclosed. An antenna apparatus includes
multiple antenna configurations, each corresponding to a radiation
pattern. A position sensor in the device detects changes in
position of the device. A processor receives the position
information from the position sensor to select an antenna
configuration and physical data rate based on the position
information.
[0017] In a further claimed embodiment, a device for transmitting a
wireless signal includes an antenna apparatus, antenna
configuration selection module, and tilt sensor. The antenna
apparatus may be configured in a variety of configurations
corresponding to various radiation patterns. The selection module
may select a first configuration of the antenna apparatus and a
second configuration the antenna apparatus based on a position of
the wireless device as detected by the tilt sensor.
[0018] In a third claimed embodiment, a wireless device for
transmitting a wireless signal is disclosed. The wireless device
includes an antenna apparatus, position sensor, and antenna
configuration selection module. Various antenna configurations,
each associated with a radiation pattern, are possible with respect
to the antenna apparatus. The position sensor detects a position of
the wireless device while execution of the antenna selection
modules causes selection of an antenna configuration based on the
detected position of the wireless device position.
[0019] In a fourth claimed embodiment, a method for adjusting a
radiation pattern is disclosed. The method includes select a first
antenna configuration corresponding to a radiation pattern when a
wireless device is in a first position; transmitting an RF signal
using the first configuration; detecting a change in the position
of the device; selecting a second antenna configuration having a
second pattern; and transmitting an RF signal using the second
configuration.
BRIEF DESCRIPTION OF THE FIGURES
[0020] FIG. 1 is a block diagram of a wireless device in
communication with one or more remote recipient devices and as is
generally known in the prior art.
[0021] FIG. 2 is a block diagram of an exemplary wireless device
transmitting an RF signal in different physical positions.
[0022] FIG. 3 is a block diagram of an exemplary wireless device,
which may be configured in different physical positions like that
disclosed in FIG. 2.
[0023] FIG. 4 is a block diagram of an exemplary software layer,
interface layer and hardware layer of the wireless device of FIG.
3.
[0024] FIG. 5 is an exemplary table of transmission control data as
may be utilized by the wireless device of FIG. 3.
[0025] FIG. 6 is an exemplary method for transmitting data based on
the physical position of a wireless device.
[0026] FIG. 7 illustrates an exemplary method for processing
feedback at a wireless device.
DETAILED DESCRIPTION
[0027] A device for a wireless RF link to a remote receiving device
includes an antenna apparatus with selectable antenna elements for
transmitting and receiving an RF signal, a signal converter for
converting between encoded signals and RF signals, a processor for
controlling the signal converter and the antenna apparatus, and a
position sensor. As the device is moved, displaced, or
re-positioned, the position sensor detects a change in position and
provides position information to the processor. The processor
receives the position information from the position sensor, selects
an antenna configuration based on the position information, and
selects a physical data rate to maximize data transmission speed.
The processor then provides an encoded signal to the signal
converter and controls the converter and antenna apparatus to
provide an RF signal through the antenna elements of the selected
antenna configuration.
[0028] For example, when the device is in a first position in a
vertical and upright position, the directional radiation pattern
resulting from a selected antenna configuration may extend
horizontally and perpendicular. When the wireless device position
is changed so that it resides on a side and in a horizontal
position (i.e., ninety degrees from the previous position), the
change in position is detected and a second antenna configuration
having a second radiation pattern. The second radiation pattern may
extend through the top of the device. If no change to the antenna
configuration was made in response to the changed position, the
selected antenna configuration would result in a radiation pattern
that extends in a vertical position (still perpendicular from the
sides of the device), and thus a weaker signal in the original
direction from the horizontal position.
[0029] A device RF signal can also be changed due to interference
from other radio transmitting devices detected at the new device
position, or disturbances in the wireless link between the system
and the remote receiving device. The processor may select an
antenna configuration with a resulting radiation pattern that
minimizes the interference. The processor may select an antenna
configuration corresponding to a maximum gain between the system
and the remote receiving device. Alternatively, the processor may
select an antenna configuration corresponding to less than maximal
gain, but corresponding to reduced interference in the wireless
link. Similarly, the processor may select a physical data rate that
maximizes data transmission speed, referred to herein as an
effective user data rate, over the wireless link to the remote
receiving device.
[0030] FIG. 2 is a block diagram of an exemplary wireless device
210 transmitting a signal while in different physical positions.
Wireless device 210 may also receive a wireless signal. While not
illustrated, the wireless device 210 of FIG. 2 includes selectable
antenna elements, a signal converter, a processor, memory, various
software elements, which may be stored in memory and executable by
a processor, and a position sensor. In the upright position,
wireless device 210 has an antenna configuration having a
horizontal radiation pattern which extends horizontally from a side
of device 210.
[0031] As wireless device 210 changes position--by approximately
ninety degrees from the vertical position to the horizontal
position in FIG. 2--and is placed on a side, the change of position
being detected by an internal position sensor, the antenna
configuration is adjusted in an according fashion and based on the
current detected position or the detected change of position such
that a radiation pattern is generated that extends outward and from
the top of wireless device 210 thereby resulting in a second
radiation pattern that extends through space in the same direction
as the first radiation pattern provided by wireless device 210. Had
the wireless pattern not been adjusted from the change in physical
position of wireless device 210, the radiation pattern would in a
vertical pattern, which may be of use only to a receiving device
immediately above or below the wireless transmitting device
210.
[0032] FIG. 3 is a block diagram of an exemplary wireless device
300, which may be configured in different physical positions like
that disclosed in FIG. 2. Wireless device 300 may be any device
that can be moved and is capable of transmitting and receiving a
wireless signal. For example, wireless device 300 may be
implemented as a cellular phone, personal digital assistant, gaming
controller, a lap top computer, or access point subject to being
moved. Wireless device 300 as illustrated in FIG. 3 includes
processor 310, accelerometer 315, tilt sensor 320, output 325,
input 330, display 335, memory 340, antenna element selector 345,
signal converter 350, antenna elements 355, network connection 360,
and data bus 365.
[0033] Processor 310 of FIG. 3 is coupled to a memory 340.
Processor 310 may be representative of a microcontroller, a
microprocessor, or an application-specific integrated circuit
(ASIC). The processor 310 may execute programs stored in memory
340. Memory 340 may also store transmission control data, which may
be retrieved by the processor 310 to control selection of the
antenna configuration of the antenna apparatus 355 and selection of
the physical data rate of the signal converter 350. Aspects of
transmission control, antenna element selection, data rate and so
forth are discussed in greater detail with respect to FIGS. 4 and
5, below.
[0034] Processor 310 of FIG. 3 is further coupled to antenna
element selector device 345 such coupling occurring via control bus
365. Antenna element selector device 345 is, in turn, coupled to
antenna apparatus 355 to allow selection of individual or groups of
antenna elements. Different combinations of selected antenna
elements may result in different radiation patterns. Processor 310
controls the antenna element selector device 345 to select a
radiation pattern corresponding to a given antenna configuration of
antenna apparatus 355.
[0035] Processor 310 is also coupled to the signal converter 350 by
the control bus 365. Processor 310 controls signal converter 350 to
select a physical data rate from multiple physical data rates at
which the signal converter 350 converts data bits into RF signals
for transmission via the antenna apparatus 355.
[0036] Processor 310 may receive packet data from an external
network 360. Received packet data is converted into data
corresponding to an 802.11 wireless protocol at signal converter
350 (e.g., a radio modulator/demodulator) at the selected physical
data rate. The converted data is transmitted as an RF transmission
via the antenna apparatus 355 to a remote node over a wireless
link.
[0037] Antenna apparatus 110 includes a plurality of individually
selectable antenna elements (not shown) within antenna apparatus
355. For example, the antenna apparatus may include two antenna
elements, three four antenna elements, or more than four antenna
elements. When selected, each of the antenna elements produces a
directional radiation pattern with gain as compared to an
omnidirectional antenna. The elements of antenna apparatus 355 are
each either directly coupled to an antenna element selector 345 or
via an intermediate individual antenna element. Antenna element
selector 345 selectively couples one or more of the antenna
elements to the signal converter 350 for transmitting a generated
RF signal. Various embodiments of the antenna apparatus 355 and the
antenna element selector device 345 are further described in
commonly owned U.S. Pat. Nos. 7,292,198; 7,193,562; and
7,362,280.
[0038] Device 300 may include any number of ports or interfaces,
which may correspond to serial communication architectures like
Universal Serial Bus (USB), RS-x, FireWire, Ethernet, SCSI, and PCI
Express or parallel communication architectures such as ATA, HIPPI,
IEEE-488, and PCMCIA for output devices 325 and input devices 330.
Examples of suitable output devices include speakers, printers,
network interfaces, and monitors. Input devices 330 may include or
be coupled to user interfaces such as alpha-numeric keypads and
keyboards, or pointing devices such as a mouse, a trackball,
stylus, or cursor direction keys.
[0039] Display system 335 may include a liquid crystal display
(LCD) or other suitable display device. Display system 335 receives
textual and graphical information, and processes the information
for output to the display device. Output 325, input 330, display
335 and memory 340 are coupled to processor 310 via one or more
buses 365.
[0040] Tilt sensor 320 can measure the tilting in two axes of a
reference plane. Tilt sensor 320 may detect pitch and roll and look
angles and may be used to detect a change of position such as
angular tilt and transmit a signal indicating the position or tilt
to processor 310. Processor 310 may then process the signal to
select an antenna configuration that provides the best coverage
signal for the current position of the wireless device 300. Tilt
sensor 320 may be implemented as one or more horizontal, vertical,
analog, or digital tilt sensors, and may be implemented as an
electrolytic, mercury, gas bubble liquid, pendulum, or other type
of tilt sensor.
[0041] For example, tilt sensor 320 may be an electrolytic tilt
sensor, which produces an electric signal to indicate how much a
structure is leaning in reference to gravity. Tilt sensor 320 may,
in the context of a wireless access point, detect whether device
300 is positioned in a horizontal position (e.g., flat against a
ceiling), in a vertical position (e.g., against a wall), or in some
other position. A tilt sensor may also determinate, in the case of
a mobile phone, determine whether the wireless device 300 is
positioned upright or is laying relatively flat on a surface such
as a table and generate a signal used in the selection of an
antenna configuration at antenna apparatus 355 and corresponding
radiation pattern.
[0042] Accelerometer 315 can measure acceleration forces
experienced by wireless device 300. These forces may be static such
as constant force of gravity pulling at the device, or dynamic such
as a force caused by moving or vibrating device 300. When an
acceleration force is detected by accelerometer 315, accelerometer
315 can provide a signal to processor 310 to report the detected
acceleration. Processor 310 can process the accelerometer signal to
aid in the selection of an antenna configuration at antenna
apparatus 355 that provides a suitable radiation pattern based on
any acceleration or change in the position of device 300. In some
cases, though tilt sensor may not detect a changed position of
device 300, accelerometer 315 may detect acceleration in device
300. In such circumstances, processor 310 may probe for an antenna
configuration that provides the best radiation pattern in response
to the accelerometer signal.
[0043] Wireless device 300 may also include a global positioning
system (GPS) device. The GPS device may be coupled to processor 310
and able to receive and process signals received from GPS
satellites or other signal sources. The location of wireless device
300 may be determined by estimating the time for the GPS device to
receive a signal from source satellites or other signal sources.
The determined location can be provided to processor 310 as a
signal by the GPS device. Processor 310 can process the GPS device
signal to aid in the selection of an antenna configuration at
antenna apparatus 355 that provides a suitable radiation pattern
based on any current position or change in the position of device
300.
[0044] Memory 340 may include programs and instructions for
execution by processor 310. When executed, the programs may select
antenna configurations based on a detected position, change in
position, or other position information provided by accelerometer
315 and/or tilt sensor 320. Selecting an antenna configuration may
include creating a table having transmission parameter control data
for each remote node. The table may include link quality metrics
for each antenna configuration. Some examples of link quality
metrics are a success ratio, an effective user data rate, a
received signal strength indicator (RSSI), and error vector
magnitude (EVM).
[0045] The success ratio can be calculated as a number of data
packets received by the particular remote receiving node 130
divided by a number of data packets transmitted to the remote
receiving node 130. The success ratio may be dependent on the
physical data rate used to transmit on the antenna configuration.
The table may be sorted by the success ratio, for example, so that
highly successful antenna configurations may be preferably
selected. A success ratio may also be calculated in a similar
fashion with respect to data successfully received from a
transmitting node.
[0046] FIG. 4 illustrates a block diagram of an exemplary software
layer 410, interface layer 460, and hardware layer 470 of the
wireless device of FIG. 3. The software layer 410 and the interface
layer 460 include instructions executed by processor 310. Hardware
layer 470 includes hardware elements of the device 100 described
with respect to FIG. 3, such as the processor 310, antenna element
selector 345, signal converter 350, and antenna apparatus 355.
Although described as software and hardware elements, aspects of
the device 300 may be implemented with any combination of software,
hardware, and firmware elements.
[0047] Software layer 410 of FIG. 4 includes a transmission control
selection module 430 and a feedback module 440. The transmission
control selection module 430 of FIG. 4 includes an antenna
configuration selection module 415, position sensor module 420, and
probe scheduler 425. The feedback module 440 is communicatively
coupled to database 435, which may be integrated in the feedback
module 440. The hardware layer 470 of FIG. 4 includes a transmitter
460 and a receiver 465.
[0048] The transmission control selection 430 is communicatively
linked to feedback module 440. Transmission control selection 430
communicates with the interface layer 460 via link 445. The
feedback module communicates with the interface layer 460 via link
450. The interface layer 460 receives packets via link 455 from
software layer 410 and sends the packets to the transmitter 475 in
the hardware layer 470. The interface layer 460 also receives
packets from receiver 465 in the hardware layer 470 and sends the
packets to the software layer 410 via link 445.
[0049] The transmission control selection 430 includes software
elements configured to select and communicate through the interface
layer 460 the current antenna configuration and the current
physical data rate based on the feedback module 440, probe
scheduler 425, or position sensor module 420. The probe scheduler
425 includes software elements configured to determine for the
transmission control selection 430 an unused antenna configuration
and an unused physical data rate based on predetermined
criteria.
[0050] One example of the predetermined criteria is determining an
unused antenna configuration after the interface layer 460
indicates as received five consecutive packets. The feedback module
440 includes software elements configured to update link quality
metrics for each antenna configuration and each physical data rate
based on feedback from the interface layer 460. The feedback module
440 is configured to maintain the link quality metrics in the
database 435. The position sensor module 420 includes software
elements that receive and process signals from accelerometer 315
and tilt sensor 320 (FIG. 3). The processing may include
determining whether to initiate selection of a new antenna
configuration based on the signals received by position sensor
module 420. The operation of the software layer 410, the interface
layer 460, and the hardware layer 470 are described below with
respect to FIG. 6 and FIG. 7.
[0051] An advantage of the device 300 is that transmission control
selection 430 may select, for example, an antenna configuration for
the antenna apparatus 355 that minimizes interference for
communicating over the wireless link to the remote receiving node
130 based on feedback (i.e., direct or indirect) from the receiving
node. The interface layer 460 indicates whether the remote
receiving node received transmitted packets on a particular antenna
configuration and physical data rate. Further, transmission
selection control 410 may select another antenna configuration for
communicating over the wireless link to the remote receiving node
130 based on the feedback, thereby changing the radiation pattern
of the antenna apparatus 355 to minimize interference in the
wireless link.
[0052] The transmission control selection 430 may select the
appropriate antenna configuration corresponding to a maximum gain
for a wireless links between the device 300 and a remote receiving
node 130. Alternatively, transmission control selection 430 may
select the antenna configuration corresponding to less than maximal
gain, but corresponding to reduced interference for the particular
position of the device. A further advantage is that transmission
control selection 430 may select the physical data rate that
provides the maximum effective user data rate at the remote
receiving node 130.
[0053] FIG. 5 illustrates an exemplary table 500 of transmission
control data as may be utilized by the wireless device of FIG. 3.
The table 500 of transmission control data may be contained in
database 435 and accessed by execution of the various software
elements of feedback module 440. Table 500 includes columns of
device position, antenna configuration, attempted transmissions,
successful transmissions, success ratio and RSSI.
[0054] The rows of the table 500 correspond to the multiple antenna
configurations of the antenna apparatus 355. For example, a table
of transmission control data for the antenna apparatus 355 having
four selectable antenna elements {A, B, C, D}, would have fifteen
possible antenna configurations comprising the set
{A|B|C|D|AB|AC|AD|BC|BD|CD|ABC|ABD|ACD|BCD|ABCD}, and up to 15 rows
of table entries.
[0055] The table 500 may be kept in the database 435 of FIG. 4 for
each of the remote receiving nodes 120-140. Each of the remote
receiving nodes 120-140 may require different antenna
configurations and/or physical data rates for optimal performance
of each of the wireless links between the device and remote
receiving nodes 120-140, therefore multiple table 500s may be kept.
For example, if five remote receiving nodes were associated with
the device 100, the processor 320 would maintain a separate table
500 for each of the five remote receiving nodes. For ease of
discussion, only a single table 500 will be discussed.
[0056] The table 500 identifies, for each of several positions for
each antenna configuration, a number of attempted transmissions and
a number of successful transmissions. Feedback module 440 updates
the number of attempted transmissions for the current antenna
configuration after interface layer 460 indicates a packet has
transmitted to a remote receiving node. The feedback module 440
updates the number of successful transmissions after the interface
layer 460 indicates the packet is received by the remote receiving
node. In some embodiments, rather than updating the number of
attempted transmissions when the device driver transmits the
packet, the feedback module 440 may update the number of attempted
transmissions after the interface layer 460 indicates whether the
remote receiving node received the packet.
[0057] The number of device positions for which transmission
control data can be collected can vary based on device resources,
designer preference, and other factors. For example, device
positions can be associated with pre-arranged ninety degree
intervals, such as flat up, vertical facing up, flat facing down,
vertical facing down. Further, the positions can be created as the
device is placed in the position. In this case, the tilt sensor 320
can provide position information to position sensor module 420,
which can in turn provide the position information to feedback
module 440 to be stored in table 500. When position information is
stored in the "device position" column, transmission control data
can be configured for different antenna configurations at the
particular position.
[0058] Table 500 also stores a success ratio and a RSSI. Although
the success ratio and the RSSI are illustrated in the table, other
link quality metrics may be stored in the table 500, such as
voltage standing wave ratio (VSWR), signal quality, bit error rate,
and error vector magnitude (EVM). The success ratio includes a
computation of the number of successful transmissions divided by
the number of attempted transmissions.
[0059] The RSSI includes an indication of the strength of the
incoming (received) signal in the receiver 480 (e.g., as measured
on an 802.11 ACK packet received from the remote receiving node 120
in response to a packet transmitted to the remote receiving node
120). The RSSI may provide a better measurement than the success
ratio for differentiating between antenna configurations. The RSSI
may provide a better link quality metric for determining the
current antenna configuration when each antenna configuration has
small values for the number of attempted transmissions and the
number of successful transmissions.
[0060] In one example, if two packets are sent to the remote
receiving node 120 using two separate antenna configurations and
are received, there may not be enough information based alone on
the respective success ratios to indicate whether one antenna
configuration is more reliable. Each of the two separate antenna
configurations has a success ratio of 100% (e.g., 2 attempted
transmissions over 2 successful transmissions). The RSSI may
provide a more precise link quality metric. If one antenna
configuration has the RSSI value of 110 and the other antenna
configuration has the RSSI value of 115, for example, then the
antenna configuration with the stronger RSSI would potentially
provide a more stable wireless link.
[0061] FIG. 6 is an exemplary method for transmitting data based on
the physical position of a wireless device. Feedback module 440 may
initialize the number of attempted transmissions and successful
transmissions in table 500 to be zero. In some embodiments, the
feedback module 440 may determine alternative initialization values
for the table 500. For example, the feedback module 440 may
determine initialization values for an antenna configuration that
provides a substantially omnidirectional radiation pattern. The
initialization values for the antenna configuration may be a high
value for the success ratio or the RSSI to force transmission
control selection 430 to select the antenna configuration for the
interface layer 460.
[0062] In step 610, packets are received for transmission using
antenna elements of antenna apparatus 355. The packets can be
received from over network 360 from another wireless device or a
wired network, through input 330, or with respect to data in memory
340 (FIG. 3). The packets may be encoded and converted to RF format
by signal converter 350. The converted packets can be provided to
interface layer 460.
[0063] A decision is made as to whether a change in device position
is detected at step 620. The position change may be detected by
tilt sensor 320, accelerometer 315, or a GPS device. Tilt sensor
320 in a wireless router device 300 may detect that the device has
been moved from a vertical position mounted to a wall to a
horizontal position on a table. A tilt sensor within a cellular
phone device 300 may detect that the phone is moved from a
horizontal position on a desk to a vertical position such as when a
user picks up the phone to view a phone display. An accelerometer
may detect that a gaming platform device 300 is being moved around
and is undergoing dynamic acceleration forces. Either an
accelerometer or a tilt sensor may detect that a laptop device 300
is moved as a user moves the device to another room. If any of tilt
sensor 320, accelerometer 315, or GPS device detects a change, the
detecting element will send a signal with position information to
position sensor module 420.
[0064] In addition to detecting a change in position, tilt sensor
320 (or another position sensor) may detect the current position of
wireless device 300 without detecting a device position change at
step 620. The position of wireless device 300 may be detected while
wireless device 300 is stationary. For example, tilt sensor 320 can
detect the wireless device position after the wireless device 300
has been stationary for a period of time or after detecting that
movement of the wireless device 300 has stopped. Tilt sensor 320
may send position information indicating the current position of
the wireless device to position module 420.
[0065] The position information may indicate a level of tilt, a
measure of acceleration, data regarding a current position of the
device, data regarding a delta in the position of the device, GPS
location data, or some other information representing motion or a
position of the device 300. Position sensor module 420 receives the
position information and sends a signal to antenna configuration
selection module 415 indicating the current device position or a
device position change occurred.
[0066] An antenna configuration for the new device position is
selected at step 660. The antenna configuration can be selected
based on the current device position or a change in detected device
position. The antenna configuration is selected from the multiple
antenna configurations in the table 500. For example, the
transmission control selection 430 selects the best ranked antenna
configuration for the current position having the highest success
ratio. The transmission control selection 430 may alternatively
select the antenna configuration having the highest RSSI for the
current position.
[0067] In step 670, transmission control selection 430 selects the
current physical data rate from the multiple physical data rates
provided by signal converter 120. The multiple physical data rates
may be defined as in the IEEE 802.11 specification for wireless
networks, including the physical data rates such as 1 Mbps, 2 Mbps,
5.5 Mbps, and 11 Mbps for IEEE 802.11b. In step 680, the interface
layer 460 sends the packet to the transmitter 460 of the hardware
layer 470. The transmitter 460 transmits the packet on the current
antenna configuration at the current physical data rate over the
wireless link to a particular remote receiving node.
[0068] Returning to step 620, if transmission control selection 430
determines that the position information does not indicate a new
current position or there is no change in the device position, then
probe scheduler 425 of transmission control selection 430
determines whether to probe another antenna configuration at step
630. Another antenna configuration can be probed if the number of
packets transmitted using the current antenna configuration
satisfies a threshold number of packets, for example five
packets.
[0069] If the probe scheduler 425 determines not to perform a probe
at step 630, transmission control selection 430 selects the current
antenna configuration for antenna apparatus 355 from the multiple
antenna configurations in the table 500 in step 650. For example,
transmission control selection 430 may select the listed antenna
configuration having the highest success ratio. In an alternative
embodiment, transmission control selection 430 may select the
antenna configuration having the highest RSSI.
[0070] Transmission control selection 430 can also select the
current physical data rate from the multiple physical data rates
provided by the signal converter 120. The multiple physical data
rates may be defined as in the IEEE 802.11 specification. The
interface layer 460 sends the packet to the transmitter 460 of the
hardware layer 470. The transmitter 460 transmits the packet on the
current antenna configuration at the current physical data rate
over a wireless link to a particular remote receiving node (e.g.,
the remote receiving node 120).
[0071] Returning to step 630, retransmission of the packet may be a
priority if the transmitted packet is not confirmed as received by
the remote receiving node 120. The need for retransmission may
indicate problems in the wireless link between the transmitting
device and the remote receiving node. When retransmitting the
packet, transmission control selection 430 attempts to determine
the antenna configuration for retransmission and the physical data
rate for retransmission that is most likely to be successful. In
step 640, the transmission control selection 430 selects an antenna
configuration for retransmission. In some embodiments, the
transmission control selection 430 selects the next lower ranked
antenna configuration in the table 500. Transmission control
selection 430 may also select a physical data rate for
retransmission. The transmitter 460 then transmits the packet in
step 680.
[0072] In some embodiments, transmission control selection 430
selects the same current antenna configuration, but incrementally
lowers the physical data rate at which the packet is retransmitted
to the remote receiving node 120. The lower physical data rate
provides the remote receiving node 120 more time to obtain a
successful reception of the packet. In other embodiments, for each
retransmission, transmission control selection 430 alternates
between selecting the next antenna configuration based on the
success ratio and the RSSI.
[0073] For example, on the first retransmission, transmission
control selection 430 selects the next lower ranked antenna
configuration based on the success ratio. If the interface layer
460 determines that the remote receiving node 120 did not indicate
reception of the packet, interface layer 460 will retransmit the
packet, and transmission control selection 430 will select the next
lower ranked antenna configuration based on the RSSI. For each
subsequent retransmission to the remote receiving node 120,
transmission control selection 430 alternates between selecting
antenna configurations based on the success ratio and the RSSI.
[0074] Referring back to step 630, when a number of consecutive
packets are successfully transmitted to and indicated as received
by remote receiving node 120, indicating stability in the wireless
link, transmission control selection 430 may determine to perform a
probe of unused antenna configurations. Probing is the temporary
changing of the current antenna configuration to one of the unused
antenna configurations for transmission of a packet. The unused
antenna configuration is any antenna configuration that is not the
current antenna configuration. Probing allows the feedback module
440 to update the values of the table 500 for the unused antenna
configurations. Probing consciously and temporarily changes the
current antenna configuration to ensure that the database 435 is
not stale. Additionally, probing allows the device 100 to
anticipate changes in the wireless link.
[0075] Based on a positive determination to perform a probe by
referencing the probe scheduler 425, transmission control selection
430 in step 640 selects an unused antenna configuration.
Transmitting on the unused antenna configuration may result in a
higher ranked success ratio than the current antenna configuration.
Further, transmission control selection 430 may probe an unused
physical data rate. In step 680, the transmitter 460 transmits the
probe packet to the remote receiving node 120.
[0076] FIG. 7 illustrates an exemplary method for processing
feedback at a wireless device. The method begins in step 705 after
transmission of the packet, as described with respect to FIG. 6. In
step 710, the feedback module 440 increments the number of
attempted transmissions 520 for the current antenna configuration.
FIG. 7 illustrates an exemplary method for processing feedback at a
wireless device.
[0077] In step 720, the interface layer 460 determines whether the
remote receiving node 120 indicated reception of the transmitted
packet. If the remote receiving node 120 indicated reception of the
packet, the feedback module 440 increments the number of successful
transmissions 530 for the current antenna configuration. In some
embodiments, whether the remote receiving node 120 indicated
reception of the packet or not, the feedback module 440 computes
the success ratio for each antenna configuration.
[0078] As previously discussed with respect to FIG. 5, feedback
module 440 determines a variety of link quality metrics which allow
the transmission control selection 430 to select an antenna
configuration. In step 730, the feedback module 440 may determine
the RSSI for each antenna configuration 510 for the remote
receiving node 120. In step 735, the feedback module 440 may
determine the effective user data rate for each physical data rate
of each antenna configuration.
[0079] In step 740, the feedback module 440 ranks each of the
antenna configurations by the success ratio for each configuration
and device position pair. In step 745, the feedback module 440 may
also rank the antenna configurations by the RSSI. In step 750,
feedback module 440 may rank each physical data rate of each
antenna configuration for the remote receiving node 120 by the
effective user data rate. This enables the transmission control
selection 430 to select a physical data rate that may have a higher
effective user data rate than the current physical data rate.
[0080] The embodiments disclosed herein are illustrative. Various
modifications or adaptations of the structures and methods
described herein may become apparent to those skilled in the art.
Such modifications, adaptations, and/or variations that rely upon
the teachings of the present disclosure and through which these
teachings have advanced the art are considered to be within the
spirit and scope of the present invention. Hence, the descriptions
and drawings herein should be limited by reference to the specific
limitations set forth in the claims appended hereto.
* * * * *