U.S. patent application number 10/931861 was filed with the patent office on 2005-02-10 for fixed wireless back haul for mobile communications using stratospheric platforms.
Invention is credited to Chang, Donald C. D., Chang, Ming U., Feria, Ying, Rosen, Harold.
Application Number | 20050032545 10/931861 |
Document ID | / |
Family ID | 33452670 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050032545 |
Kind Code |
A1 |
Chang, Donald C. D. ; et
al. |
February 10, 2005 |
Fixed wireless back haul for mobile communications using
stratospheric platforms
Abstract
A method and system for communicating includes a plurality of
cells having base units therein. Each of the base units
communicates with a plurality of users within the cells. A
communications platform is located in a stratospheric location for
transmitting and receiving information with respect to the base
units. A gateway station communicates with the communications
platform and routes signals to terrestrial networks or other user
back through the communications platform. A microcell within at
least one of the cells is used to provide coverage in a small
geographic area such as within a building. Each of the microcells
is also in communication with the gateway station through the
platform.
Inventors: |
Chang, Donald C. D.;
(Thousand Oaks, CA) ; Chang, Ming U.; (Rancho
Palos Verdes, CA) ; Feria, Ying; (Manhattan Beach,
CA) ; Rosen, Harold; (Santa Monica, CA) |
Correspondence
Address: |
THE DIRECTV GROUP INC
PATENT DOCKET ADMINISTRATION RE/R11/A109
P O BOX 956
EL SEGUNDO
CA
90245-0956
US
|
Family ID: |
33452670 |
Appl. No.: |
10/931861 |
Filed: |
September 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10931861 |
Sep 1, 2004 |
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09615894 |
Jul 14, 2000 |
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6829479 |
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Current U.S.
Class: |
455/550.1 |
Current CPC
Class: |
H04B 7/18504
20130101 |
Class at
Publication: |
455/550.1 |
International
Class: |
H04Q 007/20 |
Claims
1. A communications system comprising: a plurality of cells having
a base unit therein, each base unit directly communicating with a
plurality of users wirelessly; a communications platform located in
a stratospheric location for directly transmitting information
signals to and directly receiving information signals from said
base unit wirelessly; and a gateway station directly communicating
with the communications platform for wirelessly coupling of the
user terminal with a terrestrial-based network through the
communications platform and the base unit.
2. A communications system as recited in claim 1 wherein said users
are mobile users.
3. A communications system as recited in claim 1 further comprising
a microcell within one of the plurality of cells.
4. A communications system as recited in claim 3 wherein the
microcell is formed within a building.
5-6. (Cancelled)
7. A communications system as recited in claim 1 wherein the
communications platform is substantially stationary in the
stratospheric location.
8. A communications system as recited in claim 1 wherein said
system comprises a plurality of communications platforms.
9. A method of operating a communications system comprises the
steps of: wirelessly sending a first signal from a user terminal
directly to a base unit; wirelessly sending the first signal from
the base unit directly to a stratosphere-based platform; and
transmitting the first signal directly from the stratosphere-based
platform to a gateway station.
10. A method as recited in claim 9 further comprising the step of
transmitting the first signal from the gateway station to a
terrestrial-based network.
11. A method as recited in claim 9 further comprising the step of
transmitting the first signal from the gateway station to the
stratosphere-based platform.
12. A method as recited in claim 9 wherein the step of sending a
first signal comprises the step of sending a first signal from the
user terminal to a microcell base unit.
13-19. (Cancelled)
20. A communications system comprising: a plurality of cells; a
plurality of base units, each of said plurality of base units
directly communicating with a plurality of user terminals
wirelessly; a communications platform located in a stratospheric
location for directly transmitting information signals wirelessly
to and directly receiving information signals wirelessly from said
plurality of base units; and a gateway station directly
communicating with the communications platform for wirelessly
coupling a first user terminal of said plurality of user terminals
with a terrestrial-based network or a second user terminal of said
plurality of user terminals through the communications platform and
a respective base unit of said plurality of base units.
21. A communications system as recited in claim 20 wherein said
plurality of base units is less than said plurality of cells.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 09/615,894, filed Jul. 14, 2000, entitled
"Fixed Wireless Back Haul For Mobile Communications Using
Stratospheric Platforms", and incorporated by reference herein.
TECHNICAL FIELD
[0002] The present invention relates generally to wireless
communications and, more particularly, to a wireless communications
system that uses a high altitude communication device.
BACKGROUND ART
[0003] In this communication age, content providers are
increasingly investigating ways in which to provide more content to
users as well as interfacing with a larger group of users. The
latest communications systems use digital broadcast satellites to
broadcast to users in a forward direction. System operators have
recognized that user requests are relatively small in terms of data
compared to the amount of data broadcast from the satellite. Thus,
for example, in the DirecTV.RTM. system, user requests are
transmitted through telephone lines and programming is provided to
the users via satellite.
[0004] In addition to satellites, stratospheric platforms are
currently under development. One such stratospheric platform is
Helios that is being developed by AeroVironment. The Helios
stratospheric platform is an unmanned vehicle that can fly for
several months at a height of about 60,000 feet. Helios is a solar
powered electric plane that is modular in design and may be
configured to carry a variety of payloads. Stratospheric platforms
have numerous advantages including that capacity can be
concentrated over a populated area, transmission delays associated
with geostationary satellites are significantly reduced, the power
required for transmitting and receiving is substantially smaller
than satellites, and the elevation angles of the system are
compared to satellites and thus, if a need increases, the system
capability may be increased. In terrestrial-based cellular phone
systems, a plurality of base stations are used to communicate with
terrestrial-based users. The base stations require either
terrestrial microwave links or fiber links that communicate with a
central switching location. The growth of mobile communication
systems is ever increasing. However, to keep up with demand, new
cell sites must be added particularly in urban areas. However, it
is increasingly difficult to add new cell sites in urban areas.
[0005] It would therefore be desirable to provide a wireless
communication that allows easy expansion services to new users and
the capability of adding additional capacity in high usage
areas.
SUMMARY OF THE INVENTION
[0006] It is therefore one object of the present invention to
provide a terrestrial wireless network that is easily
expandable.
[0007] In one aspect of the invention, a communications system
comprising a plurality of cells having a base unit therein. Each of
the base units communicates with a plurality of users. A
communication platform located in a stratospheric location is used
for transmitting and receiving information from the base units. A
gateway communicates with the platform and couples the user
terminals with a terrestrial-based network through the
communications platform and the base units.
[0008] In a further aspect of the invention, a method of operating
a communications system comprises the steps of:
[0009] sending first communication signal from a first user
terminal to a base unit;
[0010] sending the first signal from the base unit to a
stratosphere-based communications platform;
[0011] transmitting the first signal from the stratosphere-based
communications platform to a gateway ground station
[0012] In a further aspect of the invention, the gateway may
transmit the first signal from the gateway ground station to a
terrestrial-based network or the first signal may be transmitted
back to the stratosphere platform and routed to another terminal
through the same or a different base unit.
[0013] One advantage of the invention is that high-speed access to
the Internet or other terrestrial networks may be obtained. Another
advantage of the invention is that a wireless system may be
expanded rapidly without having to provide a fixed communication
between a gateway center and any additional cell sites.
[0014] Other objects and features of the present invention will
become apparent when viewed in light of the detailed description of
the preferred embodiment when taken in conjunction with the
attached drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 is a system diagrammatic view of the communication
system according to the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0016] In the following description, those skilled in the art would
recognize that other embodiments and structural changes may be made
without departing from the scope of the invention.
[0017] Referring now to the FIGURE, a communications system 10 has
a cellular pattern 12 that is illustrated as a plurality of
hexagons on the earth's surface. The hexagons represent cells 14.
Each cell 14 represents a geographic area that can receive a signal
with a predetermined signal strength from a base unit 16 of a
cellular tower 18. Each base unit 16 has a transmitting and
receiving antenna 20 positioned thereon for transmitting and
receiving signals from a platform 22. Although each cell 14 is
illustrated as a hexagon, the edges of the cells are not physical
boundaries and may vary depending on the positions and strength of
the signals from cellular tower 18.
[0018] Platform 22 communicates with each base unit 16, a platform
operations center 24, and a gateway station 26. Each communication
link between platform 22 and base unit 16, platform 22 and gateway
station 26, platform 22 and platform operations center 24, and user
terminals 28 and base unit 16 is described below.
[0019] A plurality of microcells 30 may also be established within
various locations of the cellular pattern 12. As illustrated,
building 32 may contain a microcell 30 therein. Microcell 30 may
have a microcell base unit 34 that has an antenna 36 for
communicating with platform 22. The microcell base unit 34 may also
have an antenna that is used to transmit and receive wireless
information from within building 32. A plurality of microcells 30
may be established in various locations throughout the cellular
pattern 12 and more particularly within various buildings within
the cellular pattern 12. Microcell 30 acts as an additional
sub-cell within a cell.
[0020] Platform 22 is preferably a stratosphere-based platform that
remains substantially stationary relative to a geographic region on
the earth. The platform 22 is controlled by platform operations
center 24 to fly in a small radius flight path over a given spot on
the earth. Various numbers of platforms may be used to cover a
predetermined geographic region. Each platform 22 is used as a
communications node between gateway station 26 and base units
16,34. The base units 16,34 have their respective antennas 20,36
pointed toward the location of platform 22. Gateway station 26 has
an antenna 38 pointed toward platform 22. Preferably, the beam
width of the antennas is wide enough to maintain communications
link with platform 22 throughout the flight path 22. Gateway 26 is
coupled to various terrestrial networks 40 such as a public service
telephone network or various Internet providers. User terminals 28
have access to terrestrial networks 40 through base units 16,34 and
platform 22.
[0021] Platform operations center 24 acts as a control station for
platform 22 and other platforms throughout system 10. Platform
operations center 24 provides control functions, such as attitude
control, attitude management and replacement of parts and/or
platforms 22 throughout system 10. Platform operations center 24
determines when and if a specific platform 22 needs repair,
replacement, or maintenance functions performed by monitoring the
status of one or more platforms 22 in system 10.
[0022] The antennas used by platform 22, base units 16,34 and
gateway 26 allow for large data throughput in the present
invention. Since there is shorter physical distance between the
user terminals 28 and the terrestrial networks 40 than in
satellite-based systems, larger amounts of data at a larger data
rate may be provided.
[0023] The communications payload on platform 22 may, for example,
be a simple transponder design connecting the base units 16,34 to
gateway station 26. Various types of encoding schemes may be
incorporated such as code division multiple access (CDMA), time
division multiple access (TDMA), frequency division multiple access
(FDMA), or combinations of these schemes to overcome interference
caused by the worst case platform motions. Various frequencies may
be used depending on the system requirements for communication
between user terminals and base unit 16,34, between base unit 16
and platform 22, and, between platform 22 and gateway station 26.
The base units 34 of microcells 30 preferably transmit at a
frequency that does not interfere or otherwise block signals from
within the cell 14 that it transmits. Also, microcell base unit 34
may transmit at a lower power than base unit 16 of cells 14. This
allows the signals of the microcell base units 34 to be directed
into a narrow region such as a building.
[0024] In operation, signals from user terminals 28 are transmitted
to base unit 16. The base unit 16 transmits the signal to platform
22. Platform 22 transmits the signal to gateway station 26. Gateway
26 receives the signal and determines whether the signal is an
in-network signal or whether the signal is outside of the network.
If the signal is within the network, the gateway station transmits
the signal back to the platform 22. The platform 22 routes the
signal to the appropriate base unit 16 which in turn transmits a
signal to the appropriate user terminal to which the call should be
routed. If the signal is an out-of-network signal, the gateway
station 26 routes the signal to the terrestrial networks 40.
[0025] The microcells 30 work in a similar manner to that with
respect to cells 14. That is, the user terminals within the
microcells such as building 32 transmit signals to a microcell base
unit 34. The microcell base unit 34 transmits the signal to the
platform 22. The rest of the operation is the same as that
described above.
[0026] The present invention advantageously allows the wireless
services to be expanded rapidly without having to provide fixed
connection between the base unit 16,34 and the gateway station 26.
This link is often referred to as a "back haul." Also, the total
system capacity is scalable by increasing the number of platforms
associated with the system. Thus, large geographic areas may be
covered with several platforms and several gateway stations.
[0027] While particular embodiments of the invention have been
shown and described, numerous variations alternate embodiments will
occur to those skilled in the art. Accordingly, it is intended that
the invention be limited only in terms of the appended claims.
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