U.S. patent application number 12/175184 was filed with the patent office on 2009-02-05 for soft handoff using a multi-beam antenna system.
This patent application is currently assigned to ViaSat, Inc.. Invention is credited to Anthony Guy Hamel, Timothy J. Martin, Donald L. Runyon.
Application Number | 20090034475 12/175184 |
Document ID | / |
Family ID | 39892372 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090034475 |
Kind Code |
A1 |
Runyon; Donald L. ; et
al. |
February 5, 2009 |
Soft Handoff Using A Multi-Beam Antenna System
Abstract
A method for providing soft handoff between antennas in a
multi-antenna system is provided according to some embodiments of
the disclosure. A first packetized digital data stream may be
received from a satellite using a first antenna and the data stream
may include a plurality of packets that each include a header and
data. The data may be provided, forwarded or stored in memory. In
the meantime, a second packetized digital data stream is monitored.
The second packetized digital data stream may be received from the
satellite using a second antenna. The phase difference between the
first packetized digital data stream and the second packetized
digital data stream may be determined and added or subtracted from
the second packetized digital data stream. The second packetized
digital data stream may then be provided, forwarded or stored in
memory.
Inventors: |
Runyon; Donald L.; (Duluth,
GA) ; Hamel; Anthony Guy; (Encinitas, CA) ;
Martin; Timothy J.; (Carlsbad, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW LLP;VIASAT, INC (CLIENT #017018)
TWO EMBARCADERO CENTER
EIGHTH FLOOR
CA
94111
US
|
Assignee: |
ViaSat, Inc.
Carlsbad
CA
|
Family ID: |
39892372 |
Appl. No.: |
12/175184 |
Filed: |
July 17, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60961073 |
Jul 17, 2007 |
|
|
|
Current U.S.
Class: |
370/331 ;
370/328 |
Current CPC
Class: |
H04B 1/0071 20130101;
H01Q 9/0407 20130101; H04B 7/18515 20130101; H01Q 21/205 20130101;
H01Q 1/42 20130101; H04B 1/40 20130101; H04B 7/0808 20130101; H04B
1/18 20130101 |
Class at
Publication: |
370/331 ;
370/328 |
International
Class: |
H04W 4/00 20090101
H04W004/00 |
Claims
1. A method comprising: receiving a first packetized digital data
stream, wherein the first packetized digital data stream is
received from a satellite using a first antenna, and wherein the
first packetized digital data stream includes a plurality of
packets comprising a header and data; providing the data from the
first packetized digital data stream; monitoring a second
packetized digital data stream, wherein the second packetized
digital data stream is received from the satellite using a second
antenna, and wherein the second packetized digital data stream
includes a plurality of packets, each packet comprising a header
and data; determining the phase difference between the first
packetized digital data stream and the second packetized digital
data stream; subtracting the phase difference to the second
packetized digital data stream; and providing the data from the
second packetized digital data stream.
2. The method according to claim 1, wherein the determining the
phase difference determines the phase difference based on the
packet headers of the two data streams.
3. The method according to claim 1, further comprising receiving an
indication that the data from the second packetized digital data
stream should be received and written into memory.
4. The method according to claim 1, further comprising determining
that the data from the second packetized digital data stream should
be received and written into memory.
5. The method according to claim 1, further comprising determining
that the signal-to-noise ratio of the second packetized digital
data stream is greater than the signal-to-noise ration of the first
packetized digital data stream.
6. The method according to claim 1, wherein the providing includes
providing the packetized digital data stream to user through a
local network.
7. The method according to claim 1, wherein the providing includes
writing the packetized digital data stream to memory.
8. A method comprising: receiving a first packetized digital data
stream, wherein the first packetized digital data stream is
received from a satellite using a first antenna, and wherein the
first packetized digital data stream includes a plurality of
packets, each packet comprising a header and data; receiving a
second packetized digital data stream, wherein the second
packetized digital data stream is received from the satellite using
a second antenna, and wherein the second packetized digital data
stream includes a plurality of packets, each packet comprising a
header and data; determining the phase difference between the first
packetized digital data stream and the second packetized digital
data stream; subtracting the phase difference to the second
packetized digital data stream; and combining the data from the
second packetized digital data stream and the first packetized
digital data stream.
9. The method according to claim 8, wherein the determining the
phase difference determines the phase difference based on the
packet headers of the two data streams.
10. The method according to claim 8, wherein the combining combines
the data streams using maximum ratio combining.
11. The method according to claim 8, wherein the combining combines
the data streams based on the relative strength of each data
stream.
12. A satellite transceiver comprising: a plurality of antennas,
wherein at least a subset of the plurality of antennas are arranged
around a central location, wherein the azimuth coverage of the
plurality of antennas comprises at least about 360.degree., and
wherein the elevation coverage of each antenna comprises between
about 5.degree. and about 90.degree.; a processor coupled with the
plurality of antennas, wherein the processor selects at least one
antenna from the plurality of antennas for communication with a
satellite; and memory configured to store processor instructions
and data, the processor instructions including: instructions for
receiving a first packetized digital data stream, wherein the first
packetized digital data stream is received from a satellite using a
first antenna, and wherein the first packetized digital data stream
includes a plurality of packets, each packet comprising a header
and data; instructions for writing the data from the first
packetized digital data stream into memory; instructions for
monitoring a second packetized digital data stream, wherein the
second packetized digital data stream is received from the
satellite using a second antenna, and wherein the second packetized
digital data stream includes a plurality of packets, each packet
comprising a header and data; instructions for determining the
phase difference between the first packetized digital data stream
and the second packetized digital data stream; instructions for
subtracting the phase difference to the second packetized digital
data stream; and instructions for writing the data from the second
packetized digital data stream into memory.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a non-provisional, and claims the
benefit, of commonly assigned U.S. Provisional Application No.
60/961,073, filed Jul. 17, 2007, entitled "Modular Transceiver And
Multi-Beam Antenna System," the entirety of which is herein
incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] This disclosure relates in general to transceivers and, but
not by way of limitation, to modular transceivers employing
multiple antennas amongst other things.
[0003] The escalation of high bandwidth requirements for military
and commercial applications increases the need for small, modular
transceivers. Military applications, moreover, often require robust
and highly reliable systems. In some cases, the choice of
communication band may change during an operation. For example, a
military operation may require communication over the X-band during
part of a mission and communication over the Ku-band over another
part of the mission. Current transceiver devices make such
conversions extremely cumbersome.
[0004] Moreover, as a mobile unit moves, rotates, and/or turns, the
line of site between the transceiver and the mobile unit changes
over time. Finding and keeping reliable line of sight is demanding.
There is a general need in the art for reliable, modular satellite
transceivers.
BRIEF SUMMARY
[0005] A modular satellite transceiver is provided according to
some embodiments. The modular transceiver may include an RF module
and a back end module. The RF module may operate in a first band,
and may include, for example, one or more antennas, an RF front end
module, an up converter, a down converter, an analog-to-digital
converter, and a digital-to-analog converter. The back end module
may include various digital processing components and/or modules.
The RF module may be removably coupled with the back end module
such that the RF module may be replaced with another RF module
operating in a second band. During transmission the back end module
may provide at least one digital signal to the RF module; and
during reception the RF module provides at least one digital signal
to the back end module.
[0006] Another modular satellite transceiver is provided according
to some embodiments, and may include an RF module and a back end
module. The RF module may include a first antenna, a second
antenna, one or more amplifiers, a digital-to-analog converter, an
analog-to-digital converter, an up converter, and a down converter.
The RF module is configured to receive a packetized digital signal,
up convert the signal and transmit the signal to a satellite
through the first or second antenna. The RF module may also be
configured to receive a signal from the first or second antenna,
down convert the signal, and digitize the signal. Moreover, the
back end module may be removably coupled with the RF module. The
back end module may also include at least a packetization module;
and may provide and receive packetized digital signals to and from
the RF module.
[0007] In some embodiments the back end module may include
encryption and/or decryption modules. In other embodiments, the
back end module provides power conditioning to at least the RF
module. In some embodiments, the digital signal provided by the
back end module is independent of communication waveform and/or
independent of bandwidth. The back end module, in some embodiments,
may packetize transmitted data and/or depacketize received
data.
[0008] A method for sending packetized data to a satellite using a
modular transceiver that includes a back end module and an RF
module is also provided according to some embodiments. Data may be
digitally packetized at the back end module and provided to the
modular front end module. The RF module may then convert the
packetized data signal into an analog signal, up convert the analog
packetized data signal, and transmit the analog packetized data
signal toward the satellite using a first antenna.
[0009] Another method for receiving data from a satellite using a
modular transceiver that includes a back end module and an RF
module is provided according to some embodiments. A data signal is
received from a satellite with an antenna at the RF module. The
signal may then be down converted and converted from an analog
signal into a digital signal at the RF module. The signal may then
be digitally demodulated.
[0010] Another modular satellite transceiver is provided according
to some embodiments, and may include a plurality of antennas and a
processor coupled with the antennas. The plurality of antennas may,
for example, include a subset of antennas arranged around a central
location. The azimuth coverage of the plurality of antennas may
comprise up to about 360.degree.. The elevation coverage of each
antenna may comprise between about 5.degree. and about 90.degree..
The processor may select at least one antenna from the plurality of
antennas for communication with a satellite. The processor may
include various instructions including instructions for receiving
data from the satellite using a first antenna of the plurality of
antennas; instructions for monitoring a second antenna of the
plurality of antennas while the first antenna is receiving data
from the satellite, wherein the second antenna is adjacent to the
first antenna, and the second antenna covers an area adjacent to
and overlapping with the area covered by the first antenna;
instructions for determining the signal strength of the signal
detected from the second antenna; instructions for determining if
the signal strength of the signal detected from the second antenna
is greater than the signal strength of the signal detected from the
first antenna; instructions for switching to the second antenna if
the signal strength of the signal detected from the second antenna
is greater than the signal strength of the signal detected from the
first antenna; and instructions for receiving data from the
satellite using the second antenna.
[0011] A method for communicating with a satellite using a
plurality of antennas is also provided according to some
embodiments. The method may include receiving data from the
satellite using a first antenna from the plurality of antennas and
determining the signal strength of the signal detected from the
first antenna. Data may be transmitted to the satellite using the
first antenna. A second antenna adjacent to the first antenna may
partially overlap with the first antenna in coverage. The signal
strength of the signal detected from the second antenna may be
monitored. If the signal strength of the signal detected from the
second antenna is greater than the signal strength of the signal
detected from the first antenna, then data is transmitted over the
second antenna.
[0012] A method for providing a soft handoff between antennas is
provided according to some embodiments. A first packetized digital
data stream is received from a satellite using a first antenna and
the data stream may include a plurality of packets that each
include a header and data. The data is provided, forwarded or
stored in memory. In the meantime, a second packetized digital data
stream is monitored. The second packetized digital data stream may
be received from the satellite using a second antenna. The phase
difference between the first packetized digital data stream and the
second packetized digital data stream may be determined and added
or subtracted from the second packetized digital data stream. The
second packetized digital data stream may then be provided,
forwarded or stored in memory.
[0013] Another method is provided according to some embodiments.
The method includes receiving a first packetized digital data
stream from a satellite using a first antenna. The first packetized
digital data stream includes a plurality of packets, each packet
comprising a header and data. A second packetized digital data
stream is received from the satellite using a second antenna. The
phase difference between the first packetized digital data stream
and the second packetized digital data stream is determined and
subtracted from the second packetized digital data stream. The two
data streams may then be combined.
[0014] A satellite transceiver is provided according to some
embodiments. The transceiver may include a plurality of antennas, a
processor, and memory. At least a subset of the plurality of
antennas may be arranged around a central location. The azimuth
coverage of the plurality of antennas include at least about
360.degree.. The elevation coverage of each antenna includes
between about 5.degree. and about 90.degree.. The processor may be
coupled with the plurality of antennas for communication with a
satellite. The memory may be configured to store processor
instructions and data. The processor instructions may include:
Instructions for receiving a first packetized digital data stream,
wherein the first packetized digital data stream may be received
from a satellite using a first antenna, and wherein the first
packetized digital data stream includes a plurality of packets,
each packet comprising a header and data; instructions for writing
the data from the first packetized digital data stream into memory;
instructions for monitoring a second packetized digital data
stream, wherein the second packetized digital data stream may be
received from the satellite using a second antenna, and wherein the
second packetized digital data stream includes a plurality of
packets, each packet comprising a header and data; instructions for
determining the phase difference between the first packetized
digital data stream and the second packetized digital data stream;
instructions for subtracting the phase difference to the second
packetized digital data stream; and instructions for writing the
data from the second packetized digital data stream into memory, in
some embodiments, this data may be the result of the phase
difference arithmetic.
[0015] A modular transceiver with a small footprint is disclosed in
one embodiment. The small footprint may be less than about 10
inches wide by 10 inches wide by 4 inches tall. The modular
transceiver may be less than about 400 cubic inches in volume. In
one alternative, the modular transceiver may be less than about 305
cubic inches.
[0016] A transceiver with more than one antenna group is also
disclosed according to one embodiment. Each antenna group may
include at least one antenna and may be configured to transmit and
receive a signal using a single antenna within the antenna group.
In one embodiment the transceiver may include a first group, a
second group, and a third group; the first group may include three
antennas, the second group comprises three antennas, and the third
group comprises one antenna. The transceiver may provide
360.degree. azimuth coverage. The transceiver may provide at least
about 5.degree. to about 90.degree. elevation coverage.
[0017] A modular transceiver comprising a small footprint is
disclosed according to one embodiment. A transceiver comprising
more than one antenna group is also disclosed according to another
embodiment. The transceiver may comprise antenna groups each with
at least one antenna. Each antenna group may also be configured to
transmit and receive a signal using a single antenna within the
antenna group. The transceivers disclosed according to embodiments
of the invention may also provide 360.degree. azimuth coverage and
at least about 5.degree. to 90.degree. elevation coverage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1A-1C show a perspective view, top view and side view
of a radome of a modular satellite transceiver according to one
embodiment.
[0019] FIG. 2 shows antenna patches within a modular transceiver
according to one embodiment.
[0020] FIG. 3 shows an exploded view of a front end module of a
transceiver-antenna assembly according to one embodiment.
[0021] FIG. 4 shows a block diagram showing an RF module and a back
end module according to another embodiment.
[0022] FIG. 5 shows a block diagram of an antenna module with a
plurality of antennas according to one embodiment.
[0023] FIGS. 6A-6B shows a block diagram of an RF front end module
according to one embodiment.
[0024] FIG. 7A shows a block diagram of receiver components of
another RF front end module according to one embodiment.
[0025] FIG. 7B shows a block diagram of transmitter components of
another RF front end module according to one embodiment.
[0026] FIG. 8 shows a block diagram of receiver components of a
band converter module according to one embodiment.
[0027] FIG. 9 shows a block diagram of transmitter components of a
band converter module according to one embodiment.
[0028] FIG. 10 shows a block diagram showing transmission and
reception of a signal using multiple antennas according to one
embodiment.
[0029] FIG. 11 shows an RF module with an antenna module, front end
module, and a band conversion module according to one
embodiment.
[0030] FIG. 12 shows an RF module with an antenna module, front end
module, and a band conversion module according to one
embodiment.
[0031] FIG. 13 shows an RF module with an antenna module, front end
module, and a band conversion module according to one
embodiment.
[0032] FIG. 14 shows an RF module with an antenna module, front end
module, and a band conversion module according to one
embodiment.
[0033] FIG. 15 shows another block diagram of an RF module with an
antenna module, front end module, and a band conversion module
according to one embodiment.
[0034] FIG. 16 shows a block diagram showing examples of components
in an RF module and a back end module according to various
embodiments.
[0035] FIG. 17 shows a block diagram of a signal tracking system
according to one embodiment.
[0036] FIG. 18 shows a flowchart of a method for tracking a
satellite using multiple antennas according to one embodiment.
[0037] FIG. 19 shows another flowchart of a method for tracking
satellites using multiple antennas and a gyroscopic element
according to one embodiment.
[0038] FIG. 20 shows another flowchart of a method for tracking
satellites using at least three antenna groups and a gyroscopic
element according to one embodiment.
[0039] FIG. 21 shows a flowchart of a method for completing a soft
transition from one antenna to another antenna according to one
embodiment.
[0040] FIG. 22 shows a flowchart of a method for adjusting the
phase of two received signals and combining the two signals.
[0041] FIG. 23 shows an example of a data structure according to
one embodiment.
[0042] FIG. 24 shows another flowchart of a method for completing a
soft transition from one antenna to another antenna according to
one embodiment.
[0043] In the appended figures, similar components and/or features
may have the same reference label. Where the reference label is
used in the specification, the description is applicable to any one
of the similar components having the same reference label.
DETAILED DESCRIPTION OF THE INVENTION
[0044] The ensuing description provides embodiments only, and is
not intended to limit the scope, applicability or configuration of
the disclosure. Rather, the ensuing description of the
embodiment(s) will provide those skilled in the art with an
enabling description for implementing a embodiment. Various changes
may be made in the function and arrangement of elements without
departing from the spirit and scope as set forth in the appended
claims.
[0045] A modular satellite transceiver is disclosed herein in
various embodiments. The modular transceiver, in one embodiment,
may include an RF module and a back end module, the two modules may
digitally communicate with each other. For example, the back end
module may provide digital data packets to the RF module to convert
to analog, up convert, amplify and/or mix prior to transmission
through the satellite. Moreover, the module satellite transceiver,
in another embodiment, may also include a plurality of antennas.
These antennas, for example, may be arranged around a central
location. The RF module may be replaced with another RF module
configured to operate in a different communication band. For
example, a Ku band RF module may be replaced with an X band RF
module without requiring any changes to the back end module.
[0046] A satellite transceiver is also disclosed that switches
between various antennas to establish and maintain link with a
satellite in various embodiments. For example, the transceiver may
include four antennas arranged about a central location and
covering a substantial portion of the sky. The transceiver, for
example, may select a first antenna and monitor data received from
the first antenna. If no signal is received or detected or if the
signal is not strong enough to read, then the transceiver may
select and monitor a second antenna. If no signal is received or
detected or if the signal is not strong enough to read, then
another antenna is selected, and so on. When a signal is detected,
the transceiver may receive the data from the signal. In another
embodiment, as the data is being received, the transceiver monitors
the adjacent antenna or antennas. If a stronger signal is detected
from an adjacent antenna, then the transceiver switches and
receives the data from the adjacent antenna with the stronger
signal. By switching between antennas in such a fashion, line of
sight between the satellite and the transceiver may be
maintained.
[0047] In various other embodiments disclosed herein, the switching
from receiving data from a first antenna to receiving data from a
second antenna is performed using a soft handoff. According to some
embodiments, the data received is packetized into at least a header
and data. A soft handoff may include monitoring the phase of the
signal by monitoring known data sequences in the header of signals
received at the first and the second antennas. During a handoff,
the phase difference between the two signals may be subtracted from
or added to the data received from the second antenna. In various
other embodiments, more than one antenna may receive a data
signals, which may be combined using any combining technique and/or
algorithm, for example, maximum ratio combining, equal gain
combining, ratio-squared combining and/or predetection
combining.
[0048] FIGS. 1A-1C show a perspective view, top view and side view
of a radome of an RF module 100 of a modular satellite transceiver
according to one embodiment. In some embodiments, the exterior of
the RF module includes a radome 105 and/or a base plate 110. The RF
module 100 may be replaced with another RF module that operates in
a different band. For example, the original RF module 100 may
operate in the L-Band. This RF module 100 may be replaced with
another RF module 100 that operates in any other band, such as, for
example, the X-Band, Ku-Band, and/or the Ka-Band. Another
embodiment allows for field replacement of the RF module 100 and
assemblies without replacing the backend assembly.
[0049] In some embodiments, as shown, the exterior of the RF module
100 comprises a radome 105. The radome 105 may enclose a plurality
of antennas and may be coupled with a base. The radome 105 may
comprise a cylinder-like shape. Other radome 105 embodiments may
include multi-facet shapes, smooth sectional shapes blended
together or combinations of facets and smoothly varying sections
enclosing the antenna elements. In some embodiments, the modular
transceiver may be used within an airborne or land based
configuration. In some embodiments, the radome 105 may be less than
about 8.725 inches wide by about 8.725 inches wide by about 5
inches high. In another embodiment, the dimensions of the radome
105 may be less than about 10 inches wide by 10 inches wide by 5
inches high. In yet another embodiment, the radome 105 may include
a mostly cylindrical shape with a 8.275 diameter and a height of 5
inches. In another embodiment, the radome 105 height is less than
about 4 inches. Various other embodiments may include a width or
diameter of less than about 7, 7.5, 8, 8.5, 9.5, 10.5, and/or 11
inches as well as a height of less than about 3, 3.25, 3.5, 3.75,
4, 4.25, 4.5, 4.75, 5.25, 5.5, 5.75, or 6 inches. In yet other
embodiments, the radome 105 may comprise a volume less than about
400 cubic inches. Moreover, in another embodiment, the transceiver
may comprise a volume less than about 390, 380, 370, 360, 350, 340,
110, 320, 310, 305 or 300 cubic inches.
[0050] FIG. 2 shows the interior of the RF module 100 with seven
patch antennas 205 according to one embodiment. In some
embodiments, each antenna 205 may comprise, for example, a patch
antenna or another surface mounted antenna. In this example, six
antennas 205A, 205B, 205C, 205D, 205E, and 205G are arrayed in a
hexagonal pattern around a central antenna 205F. In one embodiment,
the six side antennas may be similar antennas and the top antenna
may be unique or similar. Each of the individual antennas may be
modular. For example, the antennas may each be quickly replaced in
the field. For example, an antenna may be replaced by removing the
radome 105, unsecuring the antenna, and disconnecting the
antenna.
[0051] In another embodiment of the invention, the antenna
assembly, including each of the patch antennas is modular and may
also be quickly replaced. FIG. 3 shows an exploded view of portions
of an RF module 100 according to one embodiment. As shown in the
figure, an antenna patch assembly 320 may be mounted on an antenna
housing 325 that is then connected with other circuitry 335, which
may include, for example, the RF front end module and the band
converter module, and the bottom plate 105. A mounting ring may be
used to secure the radome 105 with the base plate 110. The antenna
housing 325 and bottom plate 110 may then be coupled with a backend
module. Accordingly, the RF module 100 and the antennas therein may
be replaced by simply replacing the independent RF module 100. This
replacement may be done, for example, to replace a bad transceiver
and/or antennas, for maintenance, for upgrading and/or to change
the band of the RF module 100. The band may be an L-band, Ku-band,
X-band, Ka-band and/or any other band. Alternatively, the
transceiver may be replaced without replacing the antenna
assembly.
[0052] Cables 330, such as coaxial cables, may be used to
communicably connect each antenna with the front end module and/or
other modules. In some embodiments, to remove the antennas, these
connectors may be disconnected. In some embodiments, the RF module
may be coupled with the back end module using twisted pair.
Alternatively, the interconnection of signals between the antenna
and transceiver assembly may be made through direct connections
affixed to the respective housing such as blind-mating connector
pairs or sets.
[0053] Patch antenna configurations can comprise single or multiple
patch arrangements with driven and parasitic elements. Patch
elements may be aperture coupled, edge driven or probe driven.
Antenna elements can be single polarization with linear or circular
polarization. In another embodiment, a dual-circular polarization
patch element having a driven patch and a parasitic patch where a
quadrature (90.degree.) hybrid circuit is incorporated into a first
patch printed circuit board (PCB) assembly for enabling dual
circular polarization states. The driven patch PCB assembly is
attached to a housing 325. A parasitic patch is carried by a
substrate in the preferred embodiment and the substrate is
supported above the driven patch by a dielectric spacer.
[0054] The transceiver may be attached to a vehicle, for example,
such as a military vehicle, a boat, an airplane, a helicopter, a
car, a jeep, a truck, a Humvee (or HMMWV), a transporter, a tank,
etc., according to some embodiments. In other embodiments, the RF
module 100 may be used in military applications. There could be
different RF modules for different applications, which may be
coupled with the same backend or modem assembly. For example, there
could be a 3, 4, or 5-patch embodiment for aircraft and a 7-patch
embodiment for vehicles that both use the same transceiver
assemblies. An RF module 100 comprised of a 5-patch embodiment
having 4 side-oriented patches and one upward oriented patch can be
operated in a similar manner as in the 7-patch embodiment. Any
number of patch antennas may be used, for example, 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, or more patch antennas may be used.
[0055] In another embodiment, the present disclosure provides for a
transceiver comprising more than one antenna group. The antenna
groups may include at least one antenna and each group may be
configured to transmit and receive a signal using a single antenna
within the antenna group. For example, the transceiver may include
a first antenna group with three antennas, a second antenna group
with three antennas, and a third antenna group with the central
antenna. Thus a group may switch between antennas and send a single
signal from the antenna group. The transceiver may also provide
360.degree. azimuth coverage. The transceiver may also provide at
least about 5.degree. to about 90.degree. elevation coverage. The
elevation coverage provided by the transceiver may range from about
6.degree., 7.degree., 8.degree., 9.degree., 10.degree., 15.degree.,
20.degree., 25.degree., or 30.degree. up to about 90.degree..
[0056] Antennas arrayed in such a configuration may provide, for
example, 360.degree. azimuth coverage. Moreover, the antennas may
provide, for example, 5.degree. to 90.degree. elevation coverage.
As another example, the antennas may provide greater than
6.degree., 7.degree., 8.degree., 9.degree., 10.degree., 15.degree.,
20.degree., 25.degree., or 30.degree. elevation coverage. Other
embodiments of the invention may provide for example, three, four,
five, seven, eight, or nine patch antennas arrayed around a central
antenna. Antennas can be grouped in sub-arrays where the signal
processing within the sub-array group can be different from the
processing among the groups. For example, the elements within the
group can be phase scanned or steered whereas the groups are
subsequently switched and/or combined through signal processing.
Those skilled in the art will recognize further configurations of
other combinations of antennas and various signal processing
configurations may be included.
[0057] As shown in FIG. 10 the hardware may provide three
independent RF channels. Each path may be coupled with an antenna
or an antenna group. In some embodiments, the second and third
groups may provide an RF channel from every other antenna patch. In
another embodiment, antenna time share may be employed to determine
the best line of sight to a satellite or other communication point.
Moreover, in some embodiments, the signals may comprise spread
spectrum signals.
[0058] The multiple paths may also be used to combine the beams in
a MIMO configuration or in an array for beam-forming applications.
Each individual antenna patch may also beam-form. The beams may
also be combined to provide signal diversity. The antennas may also
transmit at various different polarizations as well as receive at
different polarizations. In yet another embodiment, the antennas
may be configured to provide beam forming for one application and
the switch between beams for a second application.
[0059] FIG. 4 shows a block diagram showing an RF module 410 and a
back end module 420 according to another embodiment. As shown, the
RF module 410, in some embodiments, includes one or more antennas
416, front end processing module 414, and a band converter 412. The
backend module 420, for example, may include a packet switching
interface 422 and a digital processor 424. The RF module 410, in
various embodiments, may include analog-to-digital converters,
digital-to-analog converters, amplifiers, low noise amplifiers, up
conversion, down conversion, generation of mixing frequency, and/or
oscillation (see FIG. 16). The backend module may include IP
protocol functions, tracking loops, power conditioning, modulation,
demodulation, IP header compression, encryption and/or decryption.
In yet other embodiments, the RF module 410 may largely perform
analog functions and the backend module 420 may largely perform
digital functions.
[0060] FIG. 5 shows a block diagram of an antenna module 416 with a
plurality of antennas 505 according to one embodiment. In this
embodiment, seven antennas 505 are shown with seven branch line
couplers 510. The branch line couplers 510 allow for polarization
selectivity. The antennas 505 for each antenna module 416 may be
selected based on the frequency band of the RF module 410. Thus, if
an RF module was configured to communicate using the Ku band, then
the antennas will be selected to operate within the Ku band. Thus
the antennas 505 are matched with the up and down converters.
Various other bands may be used.
[0061] FIG. 6A shows a block diagram of an RF module 414 according
to one embodiment. The RF module may be coupled with the antenna
module 416. As shown the RF module 414 may include duplexers 603
that provide duplexing functions for the transmit and receive
signals. In some embodiments, a nonreflective polarization switch
602, for example, may be used to switch between left-hand and
right-hand cross polarized signals to the antenna module. On the
receive line a filter 604, such as a low pass filter, may be used.
A switch 605 may be used to select between antennas within an
antenna group for receiving a single. For example, the embodiment
shown in the figure includes 3 antenna groups, from bottom to top
Group A, Group B and Group C. In this example, Group C includes a
single antenna, such as, a central antenna. Group A and Group B,
for example, each include three antennas. Any number of groups with
any number of antennas may be used. Various filters 655, 665 and an
amplifier 660 may also be included. Each receive line may also
include various amplifiers 635, 620, filters 615, 625 and/or
limiters 630 as shown in FIG. 6. Various other components may be
included.
[0062] FIG. 6B is similar to FIG. 6A, except the transmit duplexing
occurs on a group by group basis instead of an antenna by antenna
basis. Accordingly, a single group may be selected to transmit a
signal. Thus, a switch 650 is included that switches the transmit
signal between the three groups.
[0063] FIG. 7A shows a block diagram of receiver components of
another RF front end module 414 according to one embodiment. In
this embodiment, each line from an antenna includes an amplifier
705. Antenna groups A and B also include a three way switch 710
that selects from the seven antennas or a group of antennas or an
antenna within a specific group. An antenna group may include any
number of antennas. Therefore, the switch 710, in some embodiments,
may include any number of ports. Various filters 715 and 730, for
example, band pass filters, may be included along with limiters 720
and amplifiers 725. Those skilled in the art will recognize that
other processes and/or components may be used within the RF front
end module 414. Moreover, various processes and/or components may
be removed.
[0064] FIG. 7B shows a block diagram of transmitter components of
another RF front end module 414 according to one embodiment. The
transmitter components may include for example, filters 655 and
665, amplifiers 660, and/or a switch 750 with various output ports
that lead toward the antenna. Thus, during transmission, the best
antenna may be used for transmission.
[0065] FIG. 8 shows a block diagram of receiver components of a
band converter module 412 according to one embodiment. In some
embodiments, this portion of the band converter provides down
conversion for the receive line and up conversion for the transmit
line. In some embodiments, the band converter module 412 provides
down conversion of the signal received from the RF front end 414
and provides digital signal to a backend module 420. In other
embodiments, the band converter module 412 provides a
digital-to-analog processing and up conversion for digital signals
received from the back end module. Depending on the band selected
for communication with a satellite, the band convert module 412 up
converts and/or down converts a signal with the band of the RF
module. Various amplifiers 825, 830, 840, and 845, limiters 805 and
815, rectifiers 855, and filters 820 and 850 may be used. Moreover,
analog-to-digital converters 860 convert the analog signal into a
digital format. Mixers 810 are included to decode and/or demodulate
the analog data from the carrier signal. The carrier signal is
provided by the synthesizer 880. Various other optional components
are shown coupled with the synthesizer 880, such as a power divider
865, a filter(s) 870, amplifier(s) 875, etc.
[0066] FIG. 9 shows a block diagram of transmitter components of a
band converter module 412 according to one embodiment. A
digital-to-analog converter (DAC) 905 is shown along with a
modulator 915, filters 930 and 910, amplifiers 925 and 945, a
variable gain amplifier 935, and an isolation circuit 950, and an
associated DAC 940. Digital data may be received at the DAC 905. A
modulator may then up convert the analog signal to the band being
used within the RF module. The carrier signal is provided by the
synthesizer 920. While various components are shown within this
embodiment of a band converter, in other embodiments, various other
components or combinations may be used. Moreover, in other
embodiments, components may be left our or rearranged.
[0067] FIG. 10 shows a block diagram showing reception of a signal
using multiple antennas according to one embodiment. As shown,
seven antennas 416 are grouped within three groups. Group 1
includes antenna 416-1. Group 2 includes antennas 416-2, 416-3, and
416-4. Group 3 includes antennas 416-5, 416-6 and 416-7. Groups 2
and 3 include a switch 1010 that selects which antennas are being
used to transmit or receive data. Each group also includes a
duplexer 1020 that may be tied to the specific operational band of
the RF module. From the duplexer three receive channels are
provided. Only one transmit channel is provided from a transmission
switch 1030. Thus, using the three receive channels, the system may
detect the best antenna to communicate with a satellite. This best
antenna may then be used to transmit the data. On the receive side,
data may be received by combining the signal from three antennas,
or looking only at the signal from the best antenna. As the
transceiver moves and/or rotates, the best antenna may change.
[0068] FIG. 11 shows the reception side of an RF module with an
antenna module 416, front end module 414, and a band conversion
module 412 according to one embodiment. The antenna module 416
includes one or more antennas 505. In this embodiment, a single
antenna 505 is used. The front end module 414, includes two filters
1105, 1115 and an amplifier 1110. The band conversion module 416
includes a limiter 1115, and a mixer 1120 that may decode the
analog data from the carrier signal. The carrier signal is provided
by the synthesizer 1150. Various filters 1140 and 1125 may also be
used, as well as amplifiers 1130, 1145. Finally, the band
conversion module also includes an analog-to-digital converter 1135
that converts the analog data into digital data.
[0069] FIG. 12 shows the reception side of an RF module for
receiving data with an antenna module 416, front end module 414,
and a band conversion module 412 according to one embodiment. The
antenna module 416 according to this embodiment includes two
antennas and provides two receive channels to a back end
module.
[0070] FIG. 13 shows the reception side of an RF module for
receiving data with an antenna module 416, front end module 414,
and a band conversion module 412 according to one embodiment. The
antenna module 416 includes three antennas and the front end module
414 includes a switch that selects one of two antennas for
transmission and/or reception. In some embodiments, the back end
module controls the functionality of the switch, deciding which
antenna to transmit and/or receive data. A second transmission
switch may also be included that selects between all three antennas
for data transmission.
[0071] FIG. 14 shows the transmit side of an RF module for
transmitting data with an antenna module 416, front end module 414,
and a band conversion module 412 according to one embodiment. Three
antennas 505 are shown in the antenna module 416. The front end
module 414 includes a switch 1450 that selects which antenna 505
the data will be transmitted from. A filter 1445 and an amplifier
1440 may also be included in the front end module 414. The band
conversion module 412 includes a digital-to-analog converter (DAC)
1405 and a modulator 1415 that combines a carrier signal with the
data signal. The carrier signal may be provided by a synthesizer
1420. Various filters 1430, 1435, 1410 may be included, as well as
an amplifier 1425.
[0072] FIG. 15 shows another block diagram of an RF module 410 with
an antenna module 416, front end module 414, and a band conversion
module 412 according to one embodiment. The antenna module 416
includes one or more antennas and is in communication with the
front end module 414. Analog transmit and receive data is passed
between the two modules on one channel. The front end module 414
includes duplexers 1505, amplifiers 1510 and an antenna selection
module 1515. The front end module, in some embodiments, may combine
and/or separate transmit and receive signals, provide signal
amplification, and/or provide antenna selection. The front end
module 414 sends and receives analog receive and transmit data with
the band conversion module 412 as well as receives regulated power
therefrom. The band conversion module 412 includes, for example, a
power regulation module 1535, a gyro 1540 or gps, power amplifiers
1525, an RF transmit module 1530, a single or multi channel RF
receive module 1520, and/or system reference oscillator or clock
1550. The band conversion module, in some embodiments, may provide
up and down conversion functions, digital-to-analog conversions,
analog-to-digital conversions, power amplification, and/or power
regulation. The band conversion module 412, in some embodiments,
receives and transmits digital data with the back end module,
receives unregulated power and/or digital control signals. While
components and/or modules are shown as divided between various
modules, these components and/or modules may be in the same module
or in different modules from what is shown here.
[0073] FIG. 16 shows a block diagram showing examples of components
in an RF module 1605 and a back end module 1650 according to
various embodiments. The RF module 1605, for example, may include
any or all of the following in any combination. Components such as,
for example, low noise amplifiers 1612, antennas 1618, duplexers
1620, filters 1636, multiplexers 1640, switches 1638, clocks 1624,
gyroscopes 1626 and/or GPS devices 1646 may be included.
Analog-to-digital (ADC) and digital-to-analog (DAC) modules 1614,
1616 may be used to digitize and un-digitize data. Up and down
conversion 1622, 1642 may also occur within the RF module 1605.
Mixers 1632, power control 1662, phase oscillators 1634 and/or
tracking loops 1630 may be included in some embodiments. In some
embodiments, the gyro could be found within the back end module. In
some embodiments, portions of the gyro and/or GPS circuitry may be
located within the RF module 1605 and the back end module 1650.
[0074] An IP protocol module 1660 may be included in the back end
module 1650 to prepare digital data packets according to the IP
protocol. Packetization 1664, frame structure creation 1666 and/or
IP header compression 1678 may also occur within the back end
module 1650. Decryption 1670 and/or encryption 1682 of data may
also occur, in some embodiments, within the back end module.
Digital modulation 1680 and demodulation 1668, in some embodiments,
may also occur within the back end module 1650. Frequency control
1674 and/or tracking loops for finding and/or tracking satellites
1672, in some embodiments, may also occur within the back end
module. The back end module 165084 1684 may also provide regulated
power 1684 as well as accesses to a network through a network
interface card (NIC) 1686.
[0075] FIG. 17 shows a block diagram of a signal tracking system
according to one embodiment. The signal tracking system may include
a plurality of antennas 505 that are used to track a satellite or
satellites. The processor 1700 finds the best antenna for both
transmission and reception of data from the satellite. A gyroscope
1705 and/or a GPS device 1710 may be used to aide in antenna
tracking. The processor, in some embodiments, may be located within
a back end module.
[0076] FIG. 18 shows a flowchart of a method for tracking a
satellite using multiple antennas according to one embodiment. An
antenna is selected from the group of available antennas at block
1805. For example, the most recently used antenna may be chosen. As
another example, a random antenna may be selected. In other
embodiments, antenna groups may be selected rather than single
antennas. Moreover, in some embodiments, three antenna groups may
be receiving data. In such embodiments, an antenna within an
antenna group is selected or a different antenna group may be
selected. Turning back to FIG. 10, for example, antenna 416-6 may
be selected.
[0077] Returning to FIG. 18, the system searches for a signal on
the antenna at block 1810. If no signal is found, as determined at
block 1815, then an adjacent antenna or another antenna group may
be selected at block 1820. For example, turning back to FIG. 10,
antenna 416-7 may then be selected. If a signal is found on the
antenna, as determined at block 1815 of FIG. 18, data may then be
received using this antenna at block 1825. Meanwhile, the system
may monitor the signal strength of an adjacent antenna at block
1830 and determines if the adjacent antenna has a stronger signal
at block 1830. In some embodiments, the system monitors and
compares the signal-to-noise ratio of the two signals. If the
second signal is stronger, then the system switches to the adjacent
antenna at block 1840 and continues to receive data at block 1825.
An adjacent antenna may be an antenna within the same group or
within a different group. Otherwise the system continues to receive
data at block 1825.
[0078] FIG. 19 shows another flowchart of a method for tracking
satellites using multiple antennas and a gyroscopic element
according to one embodiment. This flowchart is similar to the one
shown in FIG. 18. However, in this embodiment, a gyroscope or GPS
may be used to determine which adjacent antenna to switch to. For
example, if the transceiver is mounted to an automobile that is
turning in a clockwise direction, a gyroscope may determine this
turning motion, and direct the system to select the antenna in the
counter-clockwise direction to track the satellite. Thus, at block
1920, rotation information may be received from the gyroscope if
the signal strength is not large enough as determined in block
1815. An adjacent antenna is selected based on this rotation
information at block 1925. Similarly, at block 1940 the gyro may
aid in determining an adjacent antenna, which may be selected for
monitoring at block 1945.
[0079] FIG. 20 shows another flowchart of a method for tracking
satellites using at least three antenna groups and a gyroscopic
element according to one embodiment. In this embodiment, three
antenna groups are monitored: group A, group B and group C. Groups
A and B find the best signal within their group in a manner similar
to that shown in FIG. 19. Group C, on the other hand, is a single
antenna group and data is received directly from the signal
antenna. Data from the three groups may be combined at block 2030
after the best antennas are selected from groups A and B. The
signals may be combined, for example, using maximal-ratio combining
(MRC), adaptive interference cancellation (AIC), or any other
diversity technique. Equal gain combining, switched combining
and/or selection combining may also be used in other embodiments.
In other embodiments, rather than combining the three signals, the
strongest signal from the three groups may be selected. In another
embodiment, the group C antenna may be a central antenna, and the
group B and group A antennas may be radially located antennas. The
groups may include, for example, even and odd antennas.
[0080] FIG. 21 shows a flowchart of a method for completing a soft
transition from one antenna to another antenna according to one
embodiment. Data is received at a first antenna at block 2105. The
signal from a second antenna is monitored at block 2110. In some
embodiments, the signal from the second antenna may occur in
parallel with receiving data from the first antenna. The signal may
be monitored to compare the signal strength, for example, between
the first antenna and the second antenna in the same or different
group. If the signal strength is greater in the second antenna,
then the system may choose to switch to the second antenna.
[0081] At block 2115, the phase difference between the data
received from the first antenna and the second antenna may be
determined. For example, the phase difference may be determined by
monitoring known data strings in the data headers. This phase
difference may then be subtracted from the signal received at the
second antenna at block 2120. This subtraction process may occur
digitally, in some embodiments. The signal from the second antenna
may then be received without a phase shift from the first signal
received at the first antenna.
[0082] FIG. 22 shows a flowchart of a method for adjusting the
phase of two received signals and combining the two signals. The
two signals are received at blocks 2205 and 2210. The phase
difference between the two signals may be determined at block 2215
and the first and/or second signal may be shifted according to the
phase difference at block 2220. The signals may then be combined at
block 2225.
[0083] FIG. 23 shows an example of a data structure according to
one embodiment. As described above, the phase difference between
signals received on different antennas may be determined by
monitoring known data streams in a header file. As shown, the data
structure includes a header 2305 and a data section 2310.
[0084] FIG. 24 shows another flowchart of a method for completing a
soft transition from one antenna to another antenna according to
one embodiment. This flow chart is similar to the one shown in FIG.
21. In this embodiment, however, the data is not only received at
the first antenna at block 2105; the data is also written into data
at block 2406. The signal from a second antenna is monitored at
block 2110. At block 2115, the phase difference between the data
received from the first antenna and the second antenna may be
determined. This phase difference may then be subtracted from the
signal received from the second antenna at block 2120. Similarly,
data is received from the second antenna at block 2125 and is
written into memory at block 2426.
[0085] Embodiments of the present invention may also conform to
MIL-STD-461E and MIL-STD-464 according to another embodiment of the
invention. To resist lightning strikes, high-altitude
electromagnetic pulses (HEMP) and other threats, the outer shell
and enclosure are conductive to dissipate electricity around the
circuitry. Moreover, the connecters may be HEMP protected
connectors and may include protective covers that may be engaged
when not in use. The various components of the antenna assembly
share a common ground; for example, the patch antennas, the RF
antenna element, the radome 105, and/or the antenna assembly are DC
grounded. The joints between patches may also provide conductive
paths to ground. The Radome 105 may also provide RF shielding; for
example, using the patch grounding pins. The Radome 105 and
transceiver assembly, for example, may be grounded to a vehicle,
for example, using an exterior lug or lugs. Moreover, the RF
shielded bottom cover may also provide protection from lightening
and HEMP.
[0086] Implementation of the techniques, blocks, steps and means
described above may be done in various ways. For example, these
techniques, blocks, steps and means may be implemented in hardware,
software, or a combination thereof. For a hardware implementation,
the processing units may be implemented within one or more
application specific integrated circuits (ASICs), digital signal
processors (DSPs), digital signal processing devices (DSPDs),
programmable logic devices (PLDs), field programmable gate arrays
(FPGAs), processors, controllers, micro-controllers,
microprocessors, other electronic units designed to perform the
functions described above and/or a combination thereof.
[0087] While the principles of the disclosure have been described
above in connection with specific apparatuses and methods, it is to
be clearly understood that this description is made only by way of
example and not as limitation on the scope of the disclosure.
[0088] The attached appendix shows various exemplary embodiments of
the invention in the form of a design review presentation. The
appendix is by no means meant to be limiting. Rather, the material
disclosed in the appendix is meant as exemplary only and to
illustrate various embodiments of the invention.
* * * * *