U.S. patent number RE43,137 [Application Number 11/325,696] was granted by the patent office on 2012-01-24 for filters for combined radiotelephone/gps terminals.
This patent grant is currently assigned to ATC Technologies, LLC. Invention is credited to Peter D. Karabinis.
United States Patent |
RE43,137 |
Karabinis |
January 24, 2012 |
**Please see images for:
( Certificate of Correction ) ** |
Filters for combined radiotelephone/GPS terminals
Abstract
A satellite radiotelephone system includes a space-based
component, a plurality of ancillary terrestrial components, and a
plurality of radiotelephones. The space-based component is
configured to provide wireless radiotelephone communications using
satellite radiotelephone frequencies. The plurality of ancillary
terrestrial components include a plurality of ancillary terrestrial
component antennas configured to provide wireless radiotelephone
communications using at least one of the satellite radiotelephone
frequencies in a radiation pattern that increases radiation below
the horizon compared to above the horizon. The plurality of
radiotelephones are configured to communicate with the space-based
component and with the plurality of ancillary terrestrial
components. Each radiotelephone also includes a GPS signal
processor and a GPS mode filter that is configured to suppress
energy at (1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42
MHz. Related radiotelephones and methods are also discussed.
Inventors: |
Karabinis; Peter D. (Cary,
NC) |
Assignee: |
ATC Technologies, LLC (Reston,
VA)
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Family
ID: |
43514049 |
Appl.
No.: |
11/325,696 |
Filed: |
January 4, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10074097 |
Feb 12, 2002 |
6684057 |
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60322240 |
Sep 14, 2001 |
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60393191 |
Jul 2, 2002 |
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Reissue of: |
10353548 |
Jan 29, 2003 |
6785543 |
Aug 31, 2004 |
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Current U.S.
Class: |
455/427;
455/12.1; 455/435.1; 455/13.2; 455/428; 455/63.3 |
Current CPC
Class: |
H04B
7/1853 (20130101); H04W 72/00 (20130101); H04W
16/30 (20130101); H04B 1/3805 (20130101); H04B
7/18563 (20130101); H04B 7/216 (20130101); H04W
52/367 (20130101); H04W 16/14 (20130101); H04B
7/18513 (20130101) |
Current International
Class: |
H04W
4/00 (20090101) |
Field of
Search: |
;455/430,13.1,117
;370/315,310 |
References Cited
[Referenced By]
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WO |
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Other References
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GA 27C GPS Antenna Module and attached Summary of Laboratory
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Primary Examiner: Ghebretinsae; Temesgh
Assistant Examiner: Chan; Richard
Attorney, Agent or Firm: Myers Bigel Sibley & Sajovec,
P.A.
Parent Case Text
CROSS-REFERENCE TO PROVISIONAL APPLICATION
This application .Iadd.is a reissue of U.S. patent application Ser.
No. 10/353,548 filed Jan. 29, 2003, issued as U.S. Pat. No.
6,785,543, which .Iaddend.claims the benefit of priority from
provisional Application No. 60/393,191, filed Jul. 2, 2002,
entitled Filters For Combined Satellite Radiotelephone/GPS
Terminals. .[.In addition, this application claims the benefit of
priority as a continuation-in-part application from regular U.S.
application Ser. No. 10/074,097, filed Feb. 12, 2002, which is now
U.S. Pat. No. 6,684,057 entitled Systems and Methods for Terretrial
Reuse of Cellular Satellite Frequency Spectrum, which claims the
benefit of priority from provisional Application No. 60/322,240,
filed Sep. 14, 2001, entitled Systems and Methods for Terrestrial
Re-Use of Mobile Satellite Spectrum. Each of these applications.].
.Iadd.The above referenced application .Iaddend.is assigned to the
assignee of the present application, and .[.the disclosures of each
of these applications are.]. .Iadd.the disclosure of the above
referenced application is .Iaddend.hereby incorporated herein by
reference in .[.their.]. .Iadd.its .Iaddend.entirety as if set
forth fully herein. .Iadd.The disclosures of U.S. application Ser.
No. 10/074,097 filed Feb. 12, 2002, now U.S. Pat. No. 6,684,057,
and U.S. application Ser. No. 60/322,240, filed Sep. 14, 2011 are
also incorporated herein by reference in their entirety as if set
forth fully herein..Iaddend.
Claims
What is claimed is:
1. A satellite radiotelephone system comprising: a space-based
component that is configured to provide wireless radiotelephone
communications using satellite radiotelephone frequencies; a
plurality of ancillary terrestrial components including a plurality
of ancillary terrestrial component antennas that are configured to
provide wireless radiotelephone communications using at least one
of the satellite radiotelephone frequencies in a radiation pattern
that increases radiation below the horizon compared to above the
horizon; and a plurality of radiotelephones that are configured to
communicate with the space-based component and with the plurality
of ancillary terrestrial components, the radiotelephones also
including a GPS signal receiver and a GPS mode filter that is
configured to suppress energy at and/or below (1575.42-.DELTA.)
MHz, where 0<.DELTA..ltoreq.16.42 MHz.
2. The satellite radiotelephone system according to claim 1,
wherein the GPS mode filter is configured to suppress at least 10
dB of energy at and/or below (1575.42-.DELTA.) MHz.
3. The satellite radiotelephone system according to claim 2,
wherein the GPS mode filter is configured to suppress at least 10
dB of energy at frequencies less than (1575.42-.DELTA.) MHz.
4. The satellite radiotelephone system according to claim 1,
wherein the GPS mode filter is configured to suppress at least 10
dB of energy at and below (1575.42-.DELTA.) MHz.
5. The satellite radiotelephone system according to claim 1,
wherein the radiotelephones are further configured to suppress
processing of GPS signals when actively communicating with the
space-based component and/or one of the ancillary terrestrial
components.
6. The satellite radiotelephone system according to claim 5,
wherein the GPS mode filter is coupled between an antenna and a low
noise amplifier used in reception of GPS signals.
7. The satellite radiotelephone system according to claim 1,
wherein the satellite radiotelephone frequencies comprise a
satellite downlink frequency band and a satellite uplink frequency
band and wherein GPS signals are transmitted from GPS satellites
over a GPS frequency band between the satellite downlink and uplink
frequency bands.
8. The satellite radiotelephone system according to claim 7,
wherein the satellite downlink frequency band comprises frequencies
between 1525 MHz and 1559 MHz, and wherein the satellite uplink
frequency band comprises frequencies between 1626.5 MHz and 1660.5
MHz.
9. The satellite radiotelephone system according to claim 7,
wherein the GPS frequency band comprises frequencies between 1559
MHz and 1605 MHz.
10. The satellite radiotelephone system according to claim 1,
wherein .DELTA. is greater than at least 1 MHz.
11. The satellite radiotelephone system according to claim 1,
wherein the wireless radiotelephone communications are not
subjected to the GPS mode filter.
12. The satellite radiotelephone system according to claim 1,
wherein the GPS mode filter comprises a high pass filter.
13. The satellite radiotelephone system according to claim 1,
wherein the radiotelephones are further configured to receive
incoming call pages during GPS mode operations.
14. A radiotelephone comprising: a radio front end that is
configured to provide wireless radiotelephone communications using
radiotelephone frequencies, and that is configured to receive
global positioning satellite (GPS) signals from a plurality of
global positioning satellites; a signal processor that is
configured to determine a measure of location of the radiotelephone
using GPS signals received at the radio front end when providing
GPS mode operations and that is configured to process
communications that are received at and/or transmitted from the
radio front end when providing wireless radiotelephone
communications; and a GPS mode filter that is configured to filter
GPS signals received at the radio front end before being provided
to the signal processor, wherein the GPS mode filter is configured
to suppress energy at .[.and/or.]. .Iadd.and .Iaddend.below
(1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42 MHz.
15. The radiotelephone according to claim 14, wherein the radio
front end is configured to provide radiotelephone communications
with a space-based component using satellite radiotelephone
frequencies and to provide wireless radiotelephone communications
with a plurality of ancillary terrestrial components using at least
one of the satellite radiotelephone frequencies.
16. The radiotelephone according to claim 14, wherein the wireless
radiotelephone communications are not subjected to the GPS mode
filter.
17. The radiotelephone according to claim 14, wherein the GPS mode
filter is coupled between an antenna and a low noise amplifier used
in reception of GPS signals.
18. The radiotelephone according to claim 14, wherein the GPS mode
filter is configured to suppress at least 10 dB .Iadd.of energy
.Iaddend.at (1575.42-.DELTA.) MHz.
19. The radiotelephone according to claim 18, wherein the GPS mode
filter is configured to suppress at least 10 dB of energy at
frequencies less than (1575.42-.DELTA.) MHz.
20. The radiotelephone according to claim .[.14.].
.Iadd.15.Iaddend., wherein processing of GPS signals at the signal
processor is suppressed when actively providing radiotelephone
communications with the space-based component and/or one of the
ancillary terrestrial components.
21. The radiotelephone according to claim .[.14.].
.Iadd.15.Iaddend., wherein the satellite radiotelephone frequencies
comprise a satellite downlink frequency band and a satellite uplink
frequency band and wherein GPS signals are transmitted from GPS
satellites over a GPS frequency band between the satellite downlink
and uplink frequency bands.
22. The radiotelephone according to claim 21, wherein the satellite
downlink frequency band comprises frequencies between 1525 MHz and
1559 MHz, and wherein the satellite uplink frequency band comprises
frequencies between 1626.5 MHz and 1660.5 MHz.
23. The radiotelephone according to claim 21, wherein the GPS
frequency band comprises frequencies between 1559 MHz and 1605
MHz.
24. The radiotelephone according to claim 14, wherein .DELTA. is
greater than at least 1 MHz.
25. The radiotelephone according to claim 14, wherein the GPS mode
filter comprises a high pass filter.
26. The radiotelephone according to claim 14, wherein the radio
front end is further configured to receive incoming call pages
during GPS mode operations and wherein the signal processor is
further configured to process incoming call pages during GPS
operations.
27. A method of providing radiotelephone communications at a
radiotelephone comprising a radio front end that is configured to
provide wireless radiotelephone communications using radiotelephone
frequencies, and that is configured to receive global positioning
satellite (GPS) signals from a plurality of Global positioning
satellites, the method comprising: during GPS mode operations,
suppressing energy at .[.and/or.]. .Iadd.and .Iaddend.below
(1575.42-.DELTA.) MHz for GPS signals received from the radio front
end, where 0<.DELTA..ltoreq.16.42 MHz; during GPS mode
operations, determining a measure of location of the radiotelephone
using the GPS signals having suppressed energy at .[.and/or.].
.Iadd.and .Iaddend.below (1575.42-.DELTA.) MHz; and during wireless
radiotelephone communications, processing communications that are
received at and/or transmitted from the radio front end.
28. The method according to claim 27, wherein the radio front end
is configured to provide wireless radiotelephone communications
with a space-based component using satellite radiotelephone
frequencies and to provide wireless radiotelephone communications
with a plurality of ancillary terrestrial components using at least
one of the satellite radiotelephone frequencies.
29. The method according to claim 27, wherein processing
communications that are received at and transmitted from the radio
front end during wireless radiotelephone communications comprises
processing the communications without suppressing energy of the
communications at and/or below (1575.42-.DELTA.) MHz.
30. The method according to claim 27, wherein suppressing energy at
.[.and/or.]. .Iadd.and .Iaddend.below (1575.42-.DELTA.) MHz
comprises suppressing at least 10 dB of energy at .[.and/or.].
.Iadd.and .Iaddend.below (1575.42-.DELTA.) MHz.
31. The method according to claim 30, wherein suppressing energy at
.[.and/or.]. .Iadd.and .Iaddend.(1575.42-.DELTA.) MHz comprises
suppressing at least 10 dB of energy at frequencies less than
(1575.42-.DELTA.) MHz.
32. The method according to claim 31, wherein suppressing energy at
.[.and/or.]. .Iadd.and .Iaddend.below (1575.42-.DELTA.) MHz
comprises suppressing at least 10 dB of energy at (1575.42-.DELTA.)
MHz and at frequencies less than (1575.42-.DELTA.) MHz.
33. The method according to claim .[.27.]. .Iadd.28.Iaddend.,
wherein processing of GPS signals is suppressed when actively
providing radiotelephone communications with the space-based
component and/or one of the ancillary terrestrial components.
34. The method according to claim 28, wherein the satellite
radiotelephone frequencies comprise a satellite downlink frequency
band and a satellite uplink frequency band and wherein GPS signals
are transmitted from GPS satellites over a GPS frequency band
between the satellite downlink and uplink frequency bands.
35. The method according to claim 34, wherein the satellite
downlink frequency band comprises frequencies between 1525 MHz and
1559 MHz, and wherein the satellite uplink frequency band comprises
frequencies between 1626.5 MHz and 1660.5 MHz.
36. The method according to claim 34, wherein the GPS frequency
band comprises frequencies between 1559 MHz and 1605 MHz.
37. The method according to claim 27, wherein .DELTA. is greater
than at least 1 MHz.
38. The method according to claim 27, further comprising: receiving
an incoming call page during GPS mode operations; and processing
the incoming call page during GPS operations.
39. The method according to claim 27, further comprising: during
GPS mode operations prior to determining the measure of location,
providing low noise amplification of the GPS signals having
suppressed energy at and/or below (1575.42-.DELTA.) MHz.
.Iadd.40. The satellite radiotelephone system according to claim 1
wherein the GPS mode filter is configured to suppress energy at and
below (1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42
MHz..Iaddend.
.Iadd.41. A satellite radiotelephone system comprising: a
space-based component that is configured to provide wireless
radiotelephone communications using satellite radiotelephone
frequencies; at least one ancillary terrestrial component including
at least one antenna that is configured to provide wireless
radiotelephone communications using satellite radiotelephone
frequencies in a radiation pattern that increases a radiation level
below the horizon compared to a radiation level above the horizon;
and at least one radiotelephone that is configured to communicate
with the space-based component and/or with the at least one
ancillary terrestrial component, the at least one radiotelephone
including a GPS signal processor and a GPS filter that is
configured to selectively attenuate signal energy that is
associated with Radio Frequencies (RF) at and/or below
(1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42
MHz..Iaddend.
.Iadd.42. The satellite radiotelephone system according to claim
41, wherein the GPS filter is configured to suppress at least 10 dB
of signal energy that is associated with Radio Frequencies at
and/or below (1575.42-.DELTA.) MHz..Iaddend.
.Iadd.43. The satellite radiotelephone system according to claim
41, wherein the GPS filter is a band-pass filter..Iaddend.
.Iadd.44. The satellite radiotelephone system according to claim
41, wherein the at least one radiotelephone is further configured
to suppress processing of GPS signals when communicating with the
space-based component, and/or with the at least one ancillary
terrestrial component..Iaddend.
.Iadd.45. The satellite radiotelephone system according to claim
41, wherein the GPS filter is coupled between an antenna and a low
noise amplifier used in reception of GPS signals..Iaddend.
.Iadd.46. The satellite radiotelephone system according to claim
41, wherein the satellite radiotelephone frequencies comprise a
satellite downlink frequency band and a satellite uplink frequency
band and wherein GPS signals are transmitted from GPS satellites
over a GPS frequency band between the satellite downlink and uplink
frequency bands..Iaddend.
.Iadd.47. The satellite radiotelephone system according to claim
46, wherein the satellite downlink frequency band comprises
frequencies between 1525 MHz and 1559 MHz, and wherein the
satellite uplink frequency band comprises frequencies between
1626.5 MHz and 1660.5 MHz..Iaddend.
.Iadd.48. The satellite radiotelephone system according to claim
47, wherein the GPS frequency band comprises frequencies between
1559 MHz and 1605 MHz..Iaddend.
.Iadd.49. The satellite radiotelephone system according to claim
41, wherein .DELTA. is greater than 1 MHz..Iaddend.
.Iadd.50. The satellite radiotelephone system according to claim
41, wherein the wireless radiotelephone communications are not
subjected to the GPS filter..Iaddend.
.Iadd.51. The satellite radiotelephone system according to claim
41, wherein the GPS filter comprises a high pass
filter..Iaddend.
.Iadd.52. The satellite radiotelephone system according to claim
41, wherein the at least one radiotelephone is further configured
to receive wireless radiotelephone communications and/or a page
during GPS mode operations..Iaddend.
.Iadd.53. A radiotelephone comprising: a radio front end that is
configured to provide wireless radiotelephone communications using
radiotelephone frequencies, and that is configured to receive
global positioning satellite (GPS) signals from a plurality of
global positioning satellites; a signal processor that is
configured to determine a measure of location of the radiotelephone
using GPS signals received at the radio front end when providing
GPS mode operations and that is configured to process
communications that are received at and/or transmitted from the
radio front end when providing wireless radiotelephone
communications; and a GPS filter that is configured to filter
signals received at the radio front end before being provided to
the signal processor, wherein the GPS filter is configured to
selectively attenuate signal energy that is associated with Radio
Frequencies (RF) at and below (1575.42-.DELTA.) MHz, where
0<.DELTA..ltoreq.16.42 MHz..Iaddend.
.Iadd.54. The radiotelephone according to claim 53, wherein the
radio front end is configured to provide radiotelephone
communications with a space-based component using satellite
radiotelephone frequencies, and to provide wireless radiotelephone
communications with at least one ancillary terrestrial component
using satellite radiotelephone frequencies..Iaddend.
.Iadd.55. The radiotelephone according to claim 53, wherein the
wireless radiotelephone communications are not subjected to the GPS
filter..Iaddend.
.Iadd.56. The radiotelephone according to claim 53, wherein the GPS
filter is coupled between an antenna and a low noise amplifier used
in reception of GPS signals..Iaddend.
.Iadd.57. The radiotelephone according to claim 53, wherein the GPS
filter is configured to suppress at least 10 dB of signal energy
that is associated with Radio Frequencies at and below
(1575.42-.DELTA.) MHz..Iaddend.
.Iadd.58. The radiotelephone according to claim 53, wherein the GPS
filter is a band-pass filter..Iaddend.
.Iadd.59. The radiotelephone according to claim 53, wherein
processing of GPS signals at the signal processor is suppressed
responsive to the radiotelephone transmitting wireless
radiotelephone communications..Iaddend.
.Iadd.60. The radiotelephone according to claim 53, wherein the
radiotelephone frequencies comprise a satellite downlink frequency
band and a satellite uplink frequency band and wherein GPS signals
are transmitted from GPS satellites over a GPS frequency band that
is between the satellite downlink and uplink frequency
bands..Iaddend.
.Iadd.61. The radiotelephone according to claim 60, wherein the
satellite downlink frequency band comprises frequencies between
1525 MHz and 1559 MHz, and wherein the satellite uplink frequency
band comprises frequencies between 1626.5 MHz and 1660.5
MHz..Iaddend.
.Iadd.62. The radiotelephone according to claim 60, wherein the GPS
frequency band comprises frequencies between 1559 MHz and 1605
MHz..Iaddend.
.Iadd.63. The radiotelephone according to claim 53, wherein .DELTA.
is greater than 1 MHz..Iaddend.
.Iadd.64. The radiotelephone according to claim 53, wherein the GPS
filter comprises a high pass filter..Iaddend.
.Iadd.65. The radiotelephone according to claim 53, wherein the
radio front end is further configured to receive communications
and/or a page during GPS mode operations and wherein the signal
processor is further configured to process the communications
and/or the page during GPS mode operations..Iaddend.
.Iadd.66. A method of providing radiotelephone communications and a
measure of location at a radiotelephone comprising a radio front
end that is configured to provide wireless radiotelephone
communications using radiotelephone frequencies and receive global
positioning satellite (GPS) signals from a plurality of global
positioning satellites, the method comprising: during GPS mode
operations, selectively suppressing signal energy relating to Radio
Frequencies (RF)at and below (1575.42-.DELTA.) MHz, where
0<.DELTA..ltoreq.16.42 MHz; during GPS mode operations,
determining a measure of location of the radiotelephone using the
GPS signals having suppressed energy relating to Radio Frequencies
(RF) at and below (1575.42-.DELTA.) MHz; and during wireless
radiotelephone communications, processing communications that are
received at and/or transmitted from the radio front
end..Iaddend.
.Iadd.67. The method according to claim 66, wherein the radio front
end is configured to provide wireless radiotelephone communications
with a space-based component using satellite radiotelephone
frequencies, and to provide wireless radiotelephone communications
with at least one ancillary terrestrial component using satellite
radiotelephone frequencies..Iaddend.
.Iadd.68. The method according to claim 66, wherein processing
communications that are received at and/or transmitted from the
radio front end during wireless radiotelephone communications
comprises processing the communications without subjecting the
communications to selectively suppressing energy thereof relating
to Radio Frequencies (RF) at and below (1575.42-.DELTA.)
MHz..Iaddend.
.Iadd.69. The method according to claim 66, wherein selectively
suppressing signal energy relating to Radio Frequencies (RF) at and
below (1575.42-.DELTA.) MHz comprises suppressing at least 10 dB of
signal energy relating to Radio Frequencies (RF) at and below
(1575.42-.DELTA.) MHz..Iaddend.
.Iadd.70. The method according to claim 66, wherein selectively
suppressing signal energy relating to Radio Frequencies (RF) at and
below (1575.42-.DELTA.) MHz comprises high-pass
filtering..Iaddend.
.Iadd.71. The method according to claim 66, wherein determining a
measure of location of the radiotelephone using the GPS signals is
suppressed when the radiotelephone is transmitting
communications..Iaddend.
.Iadd.72. The method according to claim 67, wherein the satellite
radiotelephone frequencies comprise a satellite downlink frequency
band and a satellite uplink frequency band and wherein GPS signals
are transmitted from GPS satellites over a GPS frequency band that
is between the satellite downlink and uplink frequency
bands..Iaddend.
.Iadd.73. The method according to claim 72, wherein the satellite
downlink frequency band comprises frequencies between 1525 MHz and
1559 MHz, and wherein the satellite uplink frequency band comprises
frequencies between 1626.5 MHz and 1660.5 MHz..Iaddend.
.Iadd.74. The method according to claim 72, wherein the GPS
frequency band comprises frequencies between 1559 MHz and 1605
MHz..Iaddend.
.Iadd.75. The method according to claim 66, wherein .DELTA. is
greater than 1 MHz..Iaddend.
.Iadd.76. The method according to claim 66, further comprising:
receiving communications and/or a page during GPS mode operations;
and processing the communications and/or the page during GPS mode
operations..Iaddend.
.Iadd.77. The method according to claim 66, further comprising:
during GPS mode operations prior to determining the measure of
location, providing low noise amplification to the GPS signals
having suppressed energy relating to Radio Frequencies at and below
(1575.42-.DELTA.) MHz..Iaddend.
.Iadd.78. A method of providing space-based and terrestrial
wireless communications, the method comprising: configuring a
space-based component to provide communications using satellite
radiotelephone frequencies; configuring at least one ancillary
terrestrial component including at least one antenna to provide
wireless radiotelephone communications using satellite
radiotelephone frequencies in a radiation pattern that increases a
radiation level below the horizon compared to a radiation level
above the horizon; and configuring at least one radiotelephone to
communicate with the space-based component and/or with the at least
one ancillary terrestrial component, the at least one
radiotelephone including a GPS signal processor and a GPS filter
that is configured to selectively attenuate signal energy that is
associated with Radio Frequencies (RF) at and/or below
(1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42
MHz..Iaddend.
.Iadd.79. The method according to claim 78, wherein the GPS filter
is configured to suppress at least 10 dB of signal energy that is
associated with Radio Frequencies at and/or below (1575.42-.DELTA.)
MHz..Iaddend.
.Iadd.80. The method according to claim 78, wherein the GPS filter
is a band-pass filter..Iaddend.
.Iadd.81. The method according to claim 78, wherein the at least
one radiotelephone is further configured to suppress processing of
GPS signals when communicating with the space-based component
and/or with the at least one ancillary terrestrial
component..Iaddend.
.Iadd.82. The method according to claim 78, wherein the GPS filter
is coupled between an antenna and a low noise amplifier used in
reception of GPS signals..Iaddend.
.Iadd.83. The method according to claim 78, wherein the satellite
radiotelephone frequencies comprise a satellite downlink frequency
band and a satellite uplink frequency band and wherein GPS signals
are transmitted from GPS satellites over a GPS frequency band that
is between the satellite downlink and uplink frequency
bands..Iaddend.
.Iadd.84. The method according to claim 83, wherein the satellite
downlink frequency band comprises frequencies between 1525 MHz and
1559 MHz, and wherein the satellite uplink frequency band comprises
frequencies between 1626.5 MHz and 1660.5 MHz..Iaddend.
.Iadd.85. The method according to claim 83, wherein the GPS
frequency band comprises frequencies between 1559 MHz and 1605
MHz..Iaddend.
.Iadd.86. The method according to claim 78, wherein .DELTA. is
greater than 1 MHz..Iaddend.
.Iadd.87. The method according to claim 78, wherein the wireless
radiotelephone communications are not subjected to the GPS
filter..Iaddend.
.Iadd.88. The method according to claim 78, wherein the GPS filter
comprises a high pass filter..Iaddend.
.Iadd.89. The method according to claim 78, wherein the at least
one radiotelephone is further configured to receive wireless
radiotelephone communications and/or a page during GPS mode
operations..Iaddend.
Description
.Iadd.MULTIPLE REISSUE APPLICATIONS.Iaddend.
.Iadd.The present application is one of multiple reissue
applications seeking to reissue U.S. Pat. No. 6,785,543. The other
related reissue application is U.S. application Ser. No.
12/705,135, filed Feb. 12, 2010..Iaddend.
FIELD OF THE INVENTION
This invention relates to radiotelephone communications systems and
methods, and more particularly to terrestrial cellular and
satellite cellular radiotelephone communications systems and
methods.
BACKGROUND OF THE INVENTION
Satellite radiotelephone communications systems and methods are
widely used for radiotelephone communications. Satellite
radiotelephone communications systems and methods generally employ
at least one space-based component, such as one or more satellites
that are configured to wirelessly communicate with a plurality of
satellite radiotelephones.
A satellite radiotelephone communications system or method may
utilize a single antenna beam covering an entire area served by the
system. Alternatively, in cellular satellite radiotelephone
communications systems and methods, multiple beams are provided,
each of which can serve distinct geographical areas in the overall
service region, to collectively serve an overall satellite
footprint. Thus, a cellular architecture similar to that used in
conventional terrestrial cellular radiotelephone systems and
methods can be implemented in cellular satellite-based systems and
methods. The satellite typically communicates with radiotelephones
over a bidirectional communications pathway, with radiotelephone
communication signals being communicated from the satellite to the
radiotelephone over a downlink or forward link, and from the
radiotelephone to the satellite over an uplink or return link.
The overall design and operation of cellular satellite
radiotelephone systems and methods are well known to those having
skill in the art, and need not be described further herein.
Moreover, as used herein, the term "radiotelephone" includes
cellular and/or satellite radiotelephones with or without a
multi-line display; Personal Communications System (PCS) terminals
that may combine a radiotelephone with data processing, facsimile
and/or data communications capabilities; Personal Digital
Assistants (PDA) that can include a radio frequency transceiver and
a pager, Internet/intranet access, Web browser, organizer, calendar
and/or a global positioning system (GPS) receiver; and/or
conventional laptop and/or palmtop computers or other appliances,
which include a radio frequency transceiver.
As is well known to those having skill in the art, terrestrial
networks can enhance cellular satellite radiotelephone system
availability, efficiency and/or economic viability by terrestrially
reusing at least some of the frequency bands that are allocated to
cellular satellite radiotelephone systems. In particular, it is
known that it may be difficult for cellular satellite
radiotelephone systems to reliably serve densely populated areas,
because the satellite signal may be blocked by high-rise structures
and/or may not penetrate into buildings. As a result, the satellite
spectrum may be underutilized or unutilized in such areas. The use
of terrestrial retransmission can reduce or eliminate this
problem.
Moreover, the capacity of the overall system can be increased
significantly by the introduction of terrestrial retransmission,
since terrestrial frequency reuse can be much denser than that of a
satellite-only system. In fact, capacity can be enhanced where it
may be mostly needed, i.e., densely populated
urban/industrial/commercial areas. As a result, the overall system
can become much more economically viable, as it may be able to
serve a much larger subscriber base. Finally, satellite
radiotelephones for a satellite radiotelephone system having a
terrestrial component within the same satellite frequency band and
using substantially the same air interface for both terrestrial and
satellite communications can be more cost effective and/or
aesthetically appealing. Conventional dual band/dual mode
alternatives, such as the well known Thuraya, Iridium and/or
Globalstar dual mode satellite/terrestrial radiotelephone systems,
may duplicate some components, which may lead to increased cost,
size and/or weight of the radiotelephone.
One example of terrestrial reuse of satellite frequencies is
described in U.S. Pat. No. 5,937,332 to the present inventor
Karabinis entitled Satellite Telecommunications Repeaters and
Retransmission Methods, the disclosure of which is hereby
incorporated herein by reference in its entirety as if set forth
fully herein. As described therein, satellite telecommunications
repeaters are provided which receive, amplify, and locally
retransmit the downlink signal received from a satellite thereby
increasing the effective downlink margin in the vicinity of the
satellite telecommunications repeaters and allowing an increase in
the penetration of uplink and downlink signals into buildings,
foliage, transportation vehicles, and other objects which can
reduce link margin. Both, portable and non-portable repeaters are
provided. See the abstract of U.S. Pat. No. 5,937,332.
In view of the above discussion, there continues to be a need for
systems and methods for terrestrial reuse of cellular satellite
frequencies that can allow improved reliability, capacity, cost
effectiveness and/or aesthetic appeal for cellular satellite
radiotelephone systems, methods and/or satellite
radiotelephones.
SUMMARY OF THE INVENTION
According to embodiments of the present invention, a satellite
radiotelephone system can include a space-based component, a
plurality of ancillary terrestrial components, and a plurality of
radiotelephones. The space-based component can be configured to
provide wireless radiotelephone communications using satellite
radiotelephone frequencies. The plurality of ancillary terrestrial
components can include a plurality of ancillary terrestrial
component antennas configured to provide wireless radiotelephone
communications using at least one of the satellite radiotelephone
frequencies in a radiation pattern that increases radiation below
the horizon compared to above the horizon. The plurality of
radiotelephones can be configured to communicate with the
space-based component and with the plurality of ancillary
terrestrial components, and the radiotelephones can also include a
GPS signal receiver/processor and a GPS mode filter configured to
selectively suppress energy at and/or below (1575.42-.DELTA.) MHz,
where 0<.DELTA..ltoreq.16.42 MHz.
The GPS mode filter can be configured to suppress at least 10 dB of
energy for at least one value of .DELTA.. More particularly, the
GPS mode filter can be configured to selectively suppress at least
10 dB of energy at and/or below (1575.42-.DELTA.) MHz. The GPS mode
filter can be further configured to suppress energy at frequencies
less than (1575.42-.DELTA.) MHz, and .DELTA. can be greater than at
least 1 MHz. Accordingly, the GPS mode filter can be a high pass
filter.
In addition, the radiotelephones can be further configured to
suppress processing of GPS signals during intervals of time when
actively communicating with the space-based component and/or one of
the ancillary terrestrial components. The wireless radiotelephone
communications can be processed without being subjected to the GPS
mode filter.
The satellite radiotelephone frequencies can include a satellite
downlink frequency band and a satellite uplink frequency band and
GPS signals can be transmitted from GPS satellites over a GPS
frequency band between the satellite downlink and uplink frequency
bands. More particularly, the satellite downlink frequency band can
include frequencies between 1525 MHz and 1559 MHz, and the
satellite uplink frequency band can include frequencies between
1626.5 MHz and 1660.5 MHz. The GPS frequency band can include
frequencies between 1559 MHz and 1605 MHz.
According to additional embodiments of the present invention, a
radiotelephone can include a radio front end, a signal processor,
and a GPS mode filter. The radio front end can be configured to
provide wireless radiotelephone communications with a space-based
component using satellite radiotelephone frequencies, to provide
wireless radiotelephone communications with a plurality of
ancillary terrestrial components using at least one of the
satellite radiotelephone frequencies, and to receive global
positioning satellite (GPS) signals from a plurality of global
positioning satellites. The signal processor can be configured to
determine a measure of location of the radiotelephone using GPS
signals received at the radio front end when providing GPS mode
operations and to process communications that are received at
and/or transmitted from the radio front end when providing wireless
radiotelephone communications. The GPS mode filter can be coupled
between the radio front end and the signal processor and configured
to filter GPS signals from the radio front end before being
provided to the signal processor. More particularly, the GPS mode
filter can be configured to suppress energy at and/or below
(1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42 MHz, and
.DELTA. can be greater than at least 1 MHz.
According to particular embodiments, wireless radiotelephone
communications are not subjected to the GPS mode filter. The GPS
mode filter can be configured to suppress at least 10 dB of energy
at and/or below (1575.42-.DELTA.) MHz, and the GPS mode filter can
be more particularly configured to suppress at least 10 dB of
energy at (1575.42-.DELTA.) MHz and at frequencies less than
(1575.42-.DELTA.) MHz. Accordingly, the GPS mode filter can be a
high pass filter. Processing of GPS signals at the signal processor
can be suppressed when actively providing radiotelephone
communications with the space-based component and/or one of the
ancillary terrestrial components.
The satellite radiotelephone frequencies can include a satellite
downlink frequency band and a satellite uplink frequency band and
GPS signals can be transmitted from GPS satellites over a GPS
frequency band between the satellite downlink and uplink frequency
bands. More particularly, the satellite downlink frequency band can
include frequencies between 1525 MHz and 1559 MHz, and the
satellite uplink frequency band can include frequencies between
1626.5 MHz and 1660.5 MHz. The GPS frequency band can include
frequencies between 1559 MHz and 1605 MHz.
According to still additional embodiments of the present invention,
satellite radiotelephone communications can be provided at a
radiotelephone comprising a radio front end that is configured to
provide wireless radiotelephone communications with a space-based
component using satellite radiotelephone frequencies, that is
configured to provide wireless radiotelephone communications with a
plurality of ancillary terrestrial components using at least one of
the satellite radiotelephone frequencies, and that is configured to
receive global positioning satellite (GPS) signals from a plurality
of Global positioning satellites. Energy can be suppressed at
and/or below (1575.42-.DELTA.) MHz for GPS signals received from
the radio front end (where 0<.DELTA..ltoreq.16.42 MHz) during
GPS mode operations, and a measure of location of the
radiotelephone can be determined using the GPS signals having
suppressed energy at (1575.42-.DELTA.) MHz during GPS mode
operations. During wireless radiotelephone communications,
communications that are received at and/or transmitted from the
radio front end can be processed. More particularly, .DELTA. can be
greater than at least 1 MHz.
Processing communications that are received at and/or transmitted
from the radio front end during wireless radiotelephone
communications can include processing the communications without
suppressing energy of the communications at and/or below
(1575.42-.DELTA.) MHz. In addition, suppressing energy at and/or
below (1575.42-.DELTA.) MHz can include suppressing at least 10 dB
of energy at and/or below (1575.42-.DELTA.) MHz. More particularly,
suppressing energy at (1575.42-.DELTA.) MHz can include suppressing
at least 10 dB of energy at frequencies or (1575.42-.DELTA.) MHz
and lower. Moreover, processing of GPS signals can be suppressed
when actively providing radiotelephone communications with the
space-based component and/or one of the ancillary terrestrial
components.
The satellite radiotelephone frequencies can include a satellite
downlink frequency band and a satellite uplink frequency band and
GPS signals can be transmitted from GPS satellites over a GPS
frequency band between the satellite downlink and uplink frequency
bands. More particularly, the satellite downlink frequency band can
include frequencies between 1525 MHz and 1559 MHz, and the
satellite uplink frequency band can include frequencies between
1626.5 MHz and 1660.5 MHz. The GPS frequency band can include
frequencies between 1559 MHz and 1605 MHz.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of cellular radiotelephone systems
and methods according to embodiments of the invention.
FIG. 2 is a block diagram of adaptive interference reducers
according to embodiments of the present invention.
FIG. 3 is a spectrum diagram that illustrates satellite L-band
frequency allocations.
FIG. 4 is a schematic diagram of cellular satellite systems and
methods according to other embodiments of the present
invention.
FIG. 5 illustrates time division duplex frame structures according
to embodiments of the present invention.
FIG. 6 is a block diagram of architectures of ancillary terrestrial
components according to embodiments of the invention.
FIG. 7 is a block diagram of architectures of reconfigurable
radiotelephones according to embodiments of the invention.
FIG. 8 graphically illustrates mapping of monotonically decreasing
power levels to frequencies according to embodiments of the present
invention.
FIG. 9 illustrates an ideal cell that is mapped to three power
regions and three associated carrier frequencies according to
embodiments of the invention.
FIG. 10 depicts a realistic cell that is mapped to three power
regions and three associated carrier frequencies according to
embodiments of the invention.
FIG. 11 illustrates two or more contiguous slots in a frame that
are unoccupied according to embodiments of the present
invention.
FIG. 12 illustrates loading of two or more contiguous slots with
lower power transmissions according to embodiments of the present
invention.
FIG. 13 is a schematic representation of an antenna of an ancillary
terrestrial component according to some embodiments of the present
invention.
FIG. 14 is a polar chart that illustrates radiation patterns of an
antenna of an ancillary terrestrial component according to some
embodiments of the present invention.
FIG. 15 graphically illustrates radiation of an antenna of an
ancillary terrestrial component according to some embodiments of
the present invention.
FIG. 16 is a block diagram of a radiotelephone including a GPS
signal receiver according to some embodiments of the present
invention.
FIG. 17 is a spectrum diagram that illustrates operation of a
filter according to some embodiments of the present invention.
FIGS. 18-21 are block diagrams of radiotelephones including GPS
signal receivers according to additional embodiments of the present
invention.
DETAILED DESCRIPTION
The present invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which typical
embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like numbers refer to like
elements throughout.
FIG. 1 is a schematic diagram of cellular satellite radiotelephone
systems and methods according to embodiments of the invention. As
shown in FIG. 1, these cellular satellite radiotelephone systems
and methods 100 include at least one Space-Based Component (SBC)
110, such as a satellite. The space-based component 110 is
configured to transmit wireless communications to a plurality of
radiotelephones 120a, 120b in a satellite footprint comprising one
or more satellite radiotelephone cells 130-130'''' over one or more
satellite radiotelephone forward link (downlink) frequencies
f.sub.D. The space-based component 110 is configured to receive
wireless communications from, for example, a first radiotelephone
120a in the satellite radiotelephone cell 130 over a satellite
radiotelephone return link (uplink) frequency f.sub.U. An ancillary
terrestrial network, comprising at least one ancillary terrestrial
component 140, which may include an antenna 140a and an electronics
system 140b (for example, at least one antenna 140a and at least
one electronics system 140b), is configured to receive wireless
communications from, for example, a second radiotelephone 120b in
the radiotelephone cell 130 over the satellite radiotelephone
uplink frequency, denoted f'.sub.U, which may be the same as
f.sub.U. Thus, as illustrated in FIG. 1, radiotelephone 120a may be
communicating with the space-based component 110 while
radiotelephone 120b may be communicating with the ancillary
terrestrial component 140. As shown in FIG. 1, the space-based
component 110 also undesirably receives the wireless communications
from the second radiotelephone 120b in the satellite radiotelephone
cell 130 over the satellite radiotelephone frequency f'.sub.U as
interference. More specifically, a potential interference path is
shown at 150. In this potential interference path 150, the return
link signal of the second radiotelephone 120b at carrier frequency
f'.sub.U interferes with satellite communications. This
interference would generally be strongest when f'.sub.U=f.sub.U,
because, in that case, the same return link frequency would be used
for space-based component and ancillary terrestrial component
communications over the same satellite radiotelephone cell, and no
spatial discrimination between satellite radiotelephone cells would
appear to exist.
Still referring to FIG. 1, embodiments of satellite radiotelephone
systems/methods 100 can include at least one gateway 160 that can
include an antenna 160a and an electronics system 160b that can be
connected to other networks 162 including terrestrial and/or other
radiotelephone networks. The gateway 160 also communicates with the
space-based component 110 over a satellite feeder link 112. The
gateway 160 also communicates with the ancillary terrestrial
component 140, generally over a terrestrial link 142.
Still referring to FIG. 1, an Interference Reducer (IR) 170a also
may be provided at least partially in the ancillary terrestrial
component electronics system 140b. Alternatively or additionally,
an interference reducer 170b may be provided at least partially in
the gateway electronics system 160b. In yet other alternatives, the
interference reducer may be provided at least partially in other
components of the cellular satellite system/method 100 instead of
or in addition to the interference reducer 170a and/or 170b. The
interference reducer is responsive to the space-based component 110
and to the ancillary terrestrial component 140, and is configured
to reduce the interference from the wireless communications that
are received by the space-based component 110 and is at least
partially generated by the second radiotelephone 120b in the
satellite radiotelephone cell 130 over the satellite radiotelephone
frequency f'.sub.U. The interference reducer 170a and/or 170b uses
the wireless communications f'.sub.U that are intended for the
ancillary terrestrial component 140 from the second radiotelephone
120b in the satellite radiotelephone cell 130 using the satellite
radiotelephone frequency f'.sub.U to communicate with the ancillary
terrestrial component 140.
In embodiments of the invention, as shown in FIG. 1, the ancillary
terrestrial component 140 generally is closer to the first and
second radiotelephones 120a and 120b, respectively, than is the
space-based component 110, such that the wireless communications
from the second radiotelephone 120b are received by the ancillary
terrestrial component 140 prior to being received by the
space-based component 110. The interference reducer 170a and/or
170b is configured to generate an interference cancellation signal
comprising, for example, at least one delayed replica of the
wireless communications from the second radiotelephone 120b that
are received by the ancillary terrestrial component 140, and to
subtract the delayed replica of the wireless communications from
the second radiotelephone 120b that are received by the ancillary
terrestrial component 140 from the wireless communications that are
received from the space-based component 110. The interference
reduction signal may be transmitted from the ancillary terrestrial
component 140 to the gateway 160 over link 142 and/or using other
conventional techniques.
Thus, adaptive interference reduction techniques may be used to at
least partially cancel the interfering signal, so that the same, or
other nearby, satellite radiotelephone uplink frequency can be used
in a given cell for communications by radiotelephones 120 with the
satellite 110 and with the ancillary terrestrial component 140.
Accordingly, all frequencies that are assigned to a given cell 130
may be used for both radiotelephone 120 communications with the
space-based component 110 and with the ancillary terrestrial
component 140. Conventional systems may avoid terrestrial reuse of
frequencies within a given satellite cell that are being used
within the satellite cell for satellite communications. Stated
differently, conventionally, only frequencies used by other
satellite cells may be candidates for terrestrial reuse within a
given satellite cell. Beam-to-beam spatial isolation that is
provided by the satellite system was relied upon to reduce or
minimize the level of interference from the terrestrial operations
into the satellite operations. In sharp contrast, embodiments of
the invention can use an interference reducer to allow all
frequencies assigned to a satellite cell to be used terrestrially
and for satellite radiotelephone communications.
Embodiments of the invention according to FIG. 1 may arise from a
realization that the return link signal from the second
radiotelephone 120b at f'.sub.U generally will be received and
processed by the ancillary terrestrial component 140 much earlier
relative to the time when it will arrive at the satellite gateway
160 from the space-based component 110 via the interference path
150. Accordingly, the interference signal at the satellite gateway
160b can be at least partially canceled. Thus, as shown in FIG. 1,
an interference cancellation signal, such as the demodulated
ancillary terrestrial component signal, can be sent to the
satellite gateway 160b by the interference reducer 170a in the
ancillary terrestrial component 140, for example using link 142. In
the interference reducer 170b at the gateway 160b, a weighted (in
amplitude and/or phase) replica of the signal may be formed using,
for example, adaptive transversal filter techniques that are well
known to those having skill in the art. Then, a transversal filter
output signal is subtracted from the aggregate received satellite
signal at frequency f'.sub.U that contains desired as well as
interference signals. Thus, the interference cancellation need not
degrade the signal-to-noise ratio of the desired signal at the
gateway 160, because a regenerated (noise-free) terrestrial signal,
for example as regenerated by the ancillary terrestrial component
140, can be used to perform interference suppression.
FIG. 2 is a block diagram of embodiments of adaptive interference
cancellers that may be located in the ancillary terrestrial
component 140, in the gateway 160, and/or in another component of
the cellular radiotelephone system 100. As shown in FIG. 2, one or
more control algorithms 204, known to those having skill in the
art, may be used to adaptively adjust the coefficients of a
plurality of transversal filters 202a-202n. Adaptive algorithms,
such as Least Mean Square Error (LMSE), Kalman, Fast Kalman, Zero
Forcing and/or various combinations thereof or other techniques may
be used. It will be understood by those having skill in the art
that the architecture of FIG. 2 may be used with an LMSE algorithm.
However, it also will be understood by those having skill in the
art that conventional architectural modifications may be made to
facilitate other control algorithms.
Additional embodiments of the invention now will be described with
reference to FIG. 3, which illustrates L-band frequency allocations
including cellular radiotelephone system forward links and return
links. As shown in FIG. 3, the space-to-ground L-band forward link
(downlink) frequencies are assigned from 1525 MHz to 1559 MHz. The
ground-to-space L-band return link (uplink) frequencies occupy the
band from 1626.5 MHz to 1660.5 MHz. Between the forward and return
L-band links lie the GPS/GLONASS radionavigation band (from 1559
MHz to 1605 MHz).
In the detailed description to follow, GPS/GLONASS will be referred
to simply as GPS for the sake of brevity. Moreover, the acronyms
ATC and SBC will be used for the ancillary terrestrial component
and the space-based component, respectively, for the sake of
brevity.
As is known to those skilled in the art, GPS receivers may be
extremely sensitive since they are designed to operate on very weak
spread-spectrum radionavigation signals that arrive on the earth
from a GPS satellite constellation. As a result, GPS receivers may
to be highly susceptible to in-band interference. ATCs that are
configured to radiate L-band frequencies in the forward satellite
band (1525 to 1559 MHz) can be designed with very sharp out-of-band
emissions filters to satisfy the stringent out-of-band spurious
emissions desires of GPS.
Referring again to FIG. 1, some embodiments of the invention can
provide systems and methods that can allow an ATC 140 to configure
itself in one of at least two modes. In accordance with a first
mode, which may be a standard mode and may provide highest
capacity, the ATC 140 transmits to the radiotelephones 120 over the
frequency range from 1525 MHz to 1559 MHz, and receives
transmissions from the radiotelephones 120 in the frequency range
from 1626.5 MHz to 1660.5 MHz, as illustrated in FIG. 3. In
contrast, in a second mode of operation, the ATC 140 transmits
wireless communications to the radiotelephones 120 over a modified
range of satellite band forward link (downlink) frequencies. The
modified range of satellite band forward link frequencies may be
selected to reduce, compared to the unmodified range of satellite
band forward link frequencies, interference with wireless receivers
such as GPS receivers that operate outside the range of satellite
band forward link frequencies.
Many modified ranges of satellite band forward link frequencies may
be provided according to embodiments of the present invention. In
some embodiments, the modified range of satellite band forward link
frequencies can be limited to a subset of the original range of
satellite band forward link frequencies, so as to provide a guard
band of unused satellite band forward link frequencies. In other
embodiments, all of the satellite band forward link frequencies are
used, but the wireless communications to the radiotelephones are
modified in a manner to reduce interference with wireless receivers
that operate outside the range of satellite band forward link
frequencies. Combinations and subcombinations of these and/or other
techniques also may be used, as will be described below.
It also will be understood that embodiments of the invention that
will now be described in connection with FIGS. 4-12 will be
described in terms of multiple mode ATCs 140 that can operate in a
first standard mode using the standard forward and return links of
FIG. 3, and in a second or alternate mode that uses a modified
range of satellite band forward link frequencies and/or a modified
range of satellite band return link frequencies. These multiple
mode ATCs can operate in the second, non-standard mode, as long as
desirable, and can be switched to standard mode otherwise. However,
other embodiments of the present invention need not provide
multiple mode ATCs but, rather, can provide ATCs that operate using
the modified range of satellite band forward link and/or return
link frequencies.
Embodiments of the invention now will be described, wherein an ATC
operates with an SBC that is configured to receive wireless
communications from radiotelephones over a first range of satellite
band return link frequencies and to transmit wireless
communications to the radiotelephones over a second range of
satellite band forward link frequencies that is spaced apart from
the first range. According to these embodiments, the ATC is
configured to use at least one time division duplex frequency to
transmit wireless communications to the radiotelephones and to
receive wireless communications from the radiotelephones at
different times. In particular, in some embodiments, the at least
one time division duplex frequency that is used to transmit
wireless communications to the radiotelephones and to receive
wireless communications from the radiotelephones at different
times, comprises a frame including a plurality of slots. At least a
first one of the slots is used to transmit wireless communications
to the radiotelephones and at least a second one of the slots is
used to receive wireless communications from the radiotelephones.
Thus, in some embodiments, the ATC transmits and receives, in Time
Division Duplex (TDD) mode, using frequencies from 1626.5 MHz to
1660.5 MHz. In some embodiments, all ATCs across the entire network
may have the stated configuration/reconfiguration flexibility. In
other embodiments, only some ATCs may be reconfigurable.
FIG. 4 illustrates satellite systems and methods 400 according to
some embodiments of the invention, including an ATC 140
communicating with a radiotelephone 120b using a carrier frequency
f''.sub.U in TDD mode. FIG. 5 illustrates an embodiment of a TDD
frame structure. Assuming full-rate GSM (eight time slots per
frame), up to four full-duplex voice circuits can be supported by
one TDD carrier. As shown in FIG. 5, the ATC 140 transmits to the
radiotelephone 120b over, for example, time slot number 0. The
radiotelephone 120b receives and replies back to the ATC 140 over,
for example, time slot number 4. Time slots number 1 and 5 may be
used to establish communications with another radiotelephone, and
so on.
A Broadcast Control CHannel (BCCH) is preferably transmitted from
the ATC 140 in standard mode, using a carrier frequency from below
any guard band exclusion region. In other embodiments, a BCCH also
can be defined using a TDD carrier. In any of these embodiments,
radiotelephones in idle mode can, per established GSM methodology,
monitor the BCCH and receive system-level and paging information.
When a radiotelephone is paged, the system decides what type of
resource to allocate to the radiotelephone in order to establish
the communications link. Whatever type of resource is allocated for
the radiotelephone communications channel (TDD mode or standard
mode), the information is communicated to the radiotelephone, for
example as part of the call initialization routine, and the
radiotelephone configures itself appropriately.
It may be difficult for the TDD mode to co-exist with the standard
mode over the same ATC, due, for example, to the ATC receiver LNA
stage. In particular, assuming a mixture of standard and TDD mode
GSM carriers over the same ATC, during the part of the frame when
the TDD carriers are used to serve the forward link (when the ATC
is transmitting TDD) enough energy may leak into the receiver front
end of the same ATC to desensitize its LNA stage.
Techniques can be used to suppress the transmitted ATC energy over
the 1600 MHz portion of the band from desensitizing the ATC's
receiver LNA, and thereby allow mixed standard mode and TDD frames.
For example, isolation between outbound and inbound ATC front ends
and/or antenna system return loss may be increased or maximized. A
switchable band-reject filter may be placed in front of the LNA
stage. This filter would be switched in the receiver chain (prior
to the LNA) during the part of the frame when the ATC is
transmitting TDD, and switched out during the rest of the time. An
adaptive interference canceller can be configured at RF (prior to
the LNA stage). If such techniques are used, suppression of the
order of 70 dB can be attained, which may allow mixed standard mode
and TDD frames. However, the ATC complexity and/or cost may
increase.
Thus, even though ATC LNA desensitization may be reduced or
eliminated, it may use significant special engineering and
attention and may not be economically worth the effort. Other
embodiments, therefore, may keep TDD ATCs pure TDD, with the
exception, perhaps, of the BCCH carrier which may not be used for
traffic but only for broadcasting over the first part of the frame,
consistent with TDD protocol. Moreover, Random Access CHannel
(RACH) bursts may be timed so that they arrive at the ATC during
the second half of the TDD frame. In some embodiments, all TDD ATCs
may be equipped to enable reconfiguration in response to a
command.
It is well recognized that during data communications or other
applications, the forward link may use transmissions at higher
rates than the return link. For example, in web browsing with a
radiotelephone, mouse clicks and/or other user selections typically
are transmitted from the radiotelephone to the system. The system,
however, in response to a user selection, may have to send large
data files to the radiotelephone. Hence, other embodiments of the
invention may be configured to enable use of an increased or
maximum number of time slots per forward GSM carrier frame, to
provide a higher downlink data rate to the radiotelephones.
Thus, when a carrier frequency is configured to provide service in
TDD mode, a decision may be made as to how many slots will be
allocated to serving the forward link, and how many will be
dedicated to the return link. Whatever the decision is, it may be
desirable that it be adhered to by all TDD carriers used by the
ATC, in order to reduce or avoid the LNA desensitization problem
described earlier. In voice communications, the partition between
forward and return link slots may be made in the middle of the
frame as voice activity typically is statistically bidirectionally
symmetrical. Hence, driven by voice, the center of the frame may be
where the TDD partition is drawn.
To increase or maximize forward link throughput in data mode, data
mode TDD carriers according to embodiments of the invention may use
a more spectrally efficient modulation and/or protocol, such as the
EDGE modulation and/or protocol, on the forward link slots. The
return link slots may be based on a less spectrally efficient
modulation and/or protocol such as the GPRS (GMSK) modulation
and/or protocol. The EDGE modulation/protocol and the GPRS
modulation/protocol are well known to those having skill in the
art, and need not be described further herein. Given an EDGE
forward/GPRS return TDD carrier strategy, up to (384/2)=192 kbps
may be supported on the forward link while on the return link the
radiotelephone may transmit at up to (115/2).apprxeq.64 kbps.
In other embodiments, it also is possible to allocate six time
slots of an eight-slot frame for the forward link and only two for
the return link. In these embodiments, for voice services, given
the statistically symmetric nature of voice, the return link
vocoder may need to be comparable with quarter-rate GSM, while the
forward link vocoder can operate at full-rate GSM, to yield six
full-duplex voice circuits per GSM TDD-mode carrier (a voice
capacity penalty of 25%). Subject to this non-symmetrical
partitioning strategy, data rates of up to (384)(6/8)=288 kbps may
be achieved on the forward link, with up to (115)(2/8).apprxeq.32
kbps on the return link.
FIG. 6 depicts an ATC architecture according to embodiments of the
invention, which can lend itself to automatic configuration between
the two modes of standard GSM and TDD GSM on command, for example,
from a Network Operations Center (NOC) via a Base Station
Controller (BSC). It will be understood that in these embodiments,
an antenna 620 can correspond to the antenna 140a of FIGS. 1 and 4,
and the remainder of FIG. 6 can correspond to the electronics
system 140b of FIGS. 1 and 4. If a reconfiguration command for a
particular carrier, or set of carriers, occurs while the carrier(s)
are active and are supporting traffic, then, via the in-band
signaling Fast Associated Control CHannel (FACCH), all affected
radiotelephones may be notified to also reconfigure themselves
and/or switch over to new resources. If carrier(s) are reconfigured
from TDD mode to standard mode, automatic reassignment of the
carrier(s) to the appropriate standard-mode ATCs, based, for
example, on capacity demand and/or reuse pattern can be initiated
by the NOC. If, on the other hand, carrier(s) are reconfigured from
standard mode to TDD mode, automatic reassignment to the
appropriate TDD-mode ATCs can take place on command from the
NOC.
Still referring to FIG. 6, a switch 610 may remain closed when
carriers are to be demodulated in the standard mode. In TDD mode,
this switch 610 may be open during the first half of the frame,
when the ATC is transmitting, and closed during the second half of
the frame, when the ATC is receiving. Other embodiments also may be
provided.
FIG. 6 assumes N transceivers per ATC sector, where N can be as
small as one, since a minimum of one carrier per sector generally
is desired. Each transceiver is assumed to operate over one GSM
carrier pair (when in standard mode) and can thus support up to
eight full-duplex voice circuits, neglecting BCCH channel overhead.
Moreover, a standard GSM carrier pair can support sixteen
full-duplex voice circuits when in half-rate GSM mode, and up to
thirty two full-duplex voice circuits when in quarter-rate GSM
mode.
When in TDD mode, the number of full duplex voice circuits may be
reduced by a factor of two, assuming the same vocoder. However, in
TDD mode, voice service can be offered via the half-rate GSM
vocoder with almost imperceptible quality degradation, in order to
maintain invariant voice capacity. FIG. 7 is a block diagram of a
reconfigurable radiotelephone architecture that can communicate
with a reconfigurable ATC architecture of FIG. 6. In FIG. 7, an
antenna 720 is provided, and the remainder of FIG. 7 can provide
embodiments of an electronics system for the radiotelephone.
It will be understood that the ability to reconfigure ATCs and
radiotelephones according to embodiments of the invention may be
obtained at a relatively small increase in cost. The cost may be
mostly in Non-Recurring Engineering (NRE) cost to develop software.
Some recurring cost may also be incurred, however, in that at least
an additional RF filter and a few electronically controlled
switches may be used per ATC and radiotelephone. All other
hardware/software can be common to standard-mode and TDD-mode
GSM.
Referring now to FIG. 8, other radiotelephone systems and methods
according to embodiments of the invention now will be described. In
these embodiments, the modified second range of satellite band
forward link frequencies includes a plurality of frequencies in the
second range of satellite band forward link frequencies that are
transmitted by the ATCs to the radiotelephones at a power level,
such as maximum power level, that monotonically decreases as a
function of (increasing) frequency. More specifically, as will be
described below, in some embodiments, the modified second range of
satellite band forward link frequencies includes a subset of
frequencies proximate to a first or second end of the range of
satellite band forward link frequencies that are transmitted by the
ATC to the radiotelephones at a power level, such as a maximum
power level, that monotonically decreases toward the first or
second end of the second range of satellite band forward link
frequencies. In still other embodiments, the first range of
satellite band return link frequencies is contained in an L-band of
satellite frequencies above GPS frequencies and the second range of
satellite band forward link frequencies is contained in the L-band
of satellite frequencies below the GPS frequencies. The modified
second range of satellite band forward link frequencies includes a
subset of frequencies proximate to an end of the second range of
satellite band forward link frequencies adjacent the GPS
frequencies that are transmitted by the ATC to the radiotelephones
at a power level, such as a maximum power level, that monotonically
decreases toward the end of the second range of satellite band
forward link frequencies adjacent the GPS frequencies.
Without being bound by any theory of operation, a theoretical
discussion of the mapping of ATC maximum power levels to carrier
frequencies according to embodiments of the present invention now
will be described. Referring to FIG. 8, let .nu.=(.rho.) represent
a mapping from the power (.rho.) domain to the frequency (.nu.)
range. The power (.rho.) is the power that an ATC uses or should
transmit in order to reliably communicate with a given
radiotelephone. This power may depend on many factors such as the
radiotelephone's distance from the ATC, the blockage between the
radiotelephone and the ATC, the level of multipath fading in the
channel, etc., and as a result, will, in general, change as a
function of time. Hence, the power used generally is determined
adaptively (iteratively) via closed-loop power control, between the
radiotelephone and ATC.
The frequency (.nu.) is the satellite carrier frequency that the
ATC uses to communicate with the radiotelephone. According to
embodiments of the invention, the mapping is a monotonically
decreasing function of the independent variable .rho..
Consequently, in some embodiments, as the maximum ATC power
increases, the carrier frequency that the ATC uses to establish
and/or maintain the communications link decreases. FIG. 8
illustrates an embodiment of a piecewise continuous monotonically
decreasing (stair-case) function. Other monotonic functions may be
used, including linear and/or nonlinear, constant and/or variable
decreases. FACCH or Slow Associated Control CHannel (SACCH)
messaging may be used in embodiments of the invention to facilitate
the mapping adaptively and in substantially real time.
FIG. 9 depicts an ideal cell according to embodiments of the
invention, where, for illustration purposes, three power regions
and three associated carrier frequencies (or carrier frequency
sets) are being used to partition a cell. For simplicity, one ATC
transmitter at the center of the idealized cell is assumed with no
sectorization. In embodiments of FIG. 9, the frequency (or
frequency set) f.sub.I is taken from substantially the upper-most
portion of the L-band forward link frequency set, for example from
substantially close to 1559 MHz (see FIG. 3). Correspondingly, the
frequency (or frequency set) f.sub.M is taken from substantially
the central portion of the L-band forward link frequency set (see
FIG. 3). In concert with the above, the frequency (or frequency
set) F.sub.O is taken from substantially the lowest portion of the
L-band forward link frequencies, for example close to 1525 MHz (see
FIG. 3).
Thus, according to embodiments of FIG. 9, if a radiotelephone is
being served within the outer-most ring of the cell, that
radiotelephone is being served via frequency f.sub.O. This
radiotelephone, being within the furthest area from the ATC, has
(presumably) requested maximum (or near maximum) power output from
the ATC. In response to the maximum (or near maximum) output power
request, the ATC uses its a priori knowledge of power-to-frequency
mapping, such as a three-step staircase function of FIG. 9. Thus,
the ATC serves the radiotelephone with a low-value frequency taken
from the lowest portion of the mobile L-band forward link frequency
set, for example, from as close to 1525 MHz as possible. This,
then, can provide additional safeguard to any GPS receiver unit
that may be in the vicinity of the ATC.
Embodiments of FIG. 9 may be regarded as idealized because they
associate concentric ring areas with carrier frequencies (or
carrier frequency sets) used by an ATC to serve its area. In
reality, concentric ring areas generally will not be the case. For
example, a radiotelephone can be close to the ATC that is serving
it, but with significant blockage between the radiotelephone and
the ATC due to a building. This radiotelephone, even though
relatively close to the ATC, may also request maximum (or near
maximum) output power from the ATC. With this in mind, FIG. 10 may
depict a more realistic set of area contours that may be associated
with the frequencies being used by the ATC to serve its territory,
according to embodiments of the invention. The frequency (or
frequency set) f.sub.I may be reused in the immediately adjacent
ATC cells owing to the limited geographical span associated with
f.sub.I relative to the distance between cell centers. This may
also hold for f.sub.M.
Referring now to FIG. 11, other modified second ranges of satellite
band forward link frequencies that can be used by ATCs according to
embodiments of the present invention now will be described. In
these embodiments, at least one frequency in the modified second
range of satellite band forward link frequencies that is
transmitted by the ATC to the radiotelephones comprises a frame
including a plurality of slots. In these embodiments, at least two
contiguous slots in the frame that is transmitted by the ATC to the
radiotelephones are left unoccupied. In other embodiments, three
contiguous slots in the frame that is transmitted by the ATC to the
radiotelephones are left unoccupied. In yet other embodiments, at
least two contiguous slots in the frame that is transmitted by the
ATC to the radiotelephones are transmitted at lower power than
remaining slots in the frame. In still other embodiments, three
contiguous slots in the frame that is transmitted by the ATC to the
radiotelephones are transmitted at lower power than remaining slots
in the frame. In yet other embodiments, the lower power slots may
be used with first selected ones of the radiotelephones that are
relatively close to the ATC and/or are experiencing relatively
small signal blockage, and the remaining slots are transmitted at
higher power to second selected ones of the radiotelephones that
are relatively far from the ATC and/or are experiencing relatively
high signal blockage.
Stated differently, in accordance with some embodiments of the
invention, only a portion of the TDMA frame is utilized. For
example, only the first four (or last four, or any contiguous four)
time slots of a full-rate GSM frame are used to support traffic.
The remaining slots are left unoccupied (empty). In these
embodiments, capacity may be lost. However, as has been described
previously, for voice services, half-rate and even quarter-rate GSM
may be invoked to gain capacity back, with some potential
degradation in voice quality. The slots that are not utilized
preferably are contiguous, such as slots 0 through 3 or 4 through 7
(or 2 through 5, etc.). The use of non-contiguous slots such as 0,
2, 4, and 6, for example, may be less desirable. FIG. 11
illustrates four slots (4-7) being used and four contiguous slots
(0-3) being empty in a GSM frame.
It has been found experimentally, according to these embodiments of
the invention, that GPS receivers can perform significantly better
when the interval between interference bursts is increased or
maximized. Without being bound by any theory of operation, this
effect may be due to the relationship between the code repetition
period of the GPS C/A code (1 msec.) and the GSM burst duration
(about 0.577 msec.). With a GSM frame occupancy comprising
alternate slots, each GPS signal code period can experience at
least one "hit", whereas a GSM frame occupancy comprising four to
five contiguous slots allows the GPS receiver to derive sufficient
clean information so as to "flywheel" through the error events.
According to other embodiments of the invention, embodiments of
FIGS. 8-10 can be combined with embodiments of FIG. 11.
Furthermore, according to other embodiments of the invention, if an
f.sub.I carrier of FIG. 9 or 10 is underutilized, because of the
relatively small footprint of the inner-most region of the cell, it
may be used to support additional traffic over the much larger
outermost region of the cell.
Thus, for example, assume that only the first four slots in each
frame of f.sub.I are being used for inner region traffic. In
embodiments of FIGS. 8-10, these four f.sub.I slots are carrying
relatively low power bursts, for example of the order of 100 mW or
less, and may, therefore, appear as (almost) unoccupied from an
interference point of view. Loading the remaining four (contiguous)
time slots of f.sub.I with relatively high-power bursts may have
negligible effect on a GPS receiver because the GPS receiver would
continue to operate reliably based on the benign contiguous time
interval occupied by the four low-power GSM bursts. FIG. 12
illustrates embodiments of a frame at carrier f.sub.I supporting
four low-power (inner interval) users and four high-power (outer
interval) users. In fact, embodiments illustrated in FIG. 12 may be
a preferred strategy for the set of available carrier frequencies
that are closest to the GPS band. These embodiments may avoid undue
capacity loss by more fully loading the carrier frequencies.
The experimental finding that interference from GSM carriers can be
relatively benign to GPS receivers provided that no more than, for
example, 5 slots per 8 slot GSM frame are used in a contiguous
fashion can be very useful. It can be particularly useful since
this experimental finding may hold even when the GSM carrier
frequency is brought very close to the GPS band (as close as 1558.5
MHz) and the power level is set relatively high. For example, with
five contiguous time slots per frame populated, the worst-case
measured GPS receiver may attain at least 30 dB of desensitization
margin, over the entire ATC service area, even when the ATC is
radiating at 1558.5 MHz. With four contiguous time slots per frame
populated, an additional 10 dB desensitization margin may be gained
for a total of 40 dB for the worst-case measured GPS receiver, even
when the ATC is radiating at 1558.5 MHz.
There still may be concern about the potential loss in network
capacity (especially in data mode) that may be incurred over the
frequency interval where embodiments of FIG. 11 are used to
underpopulate the frame. Moreover, even though embodiments of FIG.
12 can avoid capacity loss by fully loading the carrier, they may
do so subject to the constraint of filling up the frame with both
low-power and high-power users. Moreover, if forward link carriers
are limited to 5 contiguous high power slots per frame, the maximum
forward link data rate per carrier that may be aimed at a
particular user, may become proportionately less.
Therefore, in other embodiments, carriers which are subject to
contiguous empty/low power slots are not used for the forward link.
Instead, they are used for the return link. Consequently, in some
embodiments, at least part of the ATC is configured in reverse
frequency mode compared to the SBC in order to allow maximum data
rates over the forward link throughout the entire network. On the
reverse frequency return link, a radiotelephone may be limited to a
maximum of 5 slots per frame, which can be adequate for the return
link. Whether the five available time slots per frame, on a reverse
frequency return link carrier, are assigned to one radiotelephone
or to five different radiotelephones, they can be assigned
contiguously in these embodiments. As was described in connection
with FIG. 12, these five contiguous slots can be assigned to
high-power users while the remaining three slots may be used to
serve low-power users.
Other embodiments may be based on operating the ATC entirely in
reverse frequency mode compared to the SBC. In these embodiments,
an ATC transmits over the satellite return link frequencies while
radiotelephones respond over the satellite forward link
frequencies. If sufficient contiguous spectrum exists to support
CDMA technologies, and in particular the emerging Wideband-CDMA 3G
standard, the ATC forward link can be based on Wideband-CDMA to
increase or maximize data throughput capabilities. Interference
with GPS may not be an issue since the ATCs transmit over the
satellite return link in these embodiments. Instead, interference
may become a concern for the radiotelephones. Based, however, on
embodiments of FIGS. 11-12, the radiotelephones can be configured
to transmit GSM since ATC return link rates are expected, in any
event, to be lower than those of the forward link. Accordingly, the
ATC return link may employ GPRS-based data modes, possibly even
EDGE. Thus, return link carriers that fall within a predetermined
frequency interval from the GPS band-edge of 1559 MHz, can be under
loaded, per embodiments of FIG. 11 or 12, to satisfy GPS
interference concerns.
Finally, other embodiments may use a partial or total reverse
frequency mode and may use CDMA on both forward and return links.
In these embodiments, the ATC forward link to the radiotelephones
utilizes the frequencies of the satellite return link (1626.5 MHz
to 1660.5 MHz) whereas the ATC return link from the radiotelephones
uses the frequencies of the satellite forward link (1525 MHz to
1559 MHz). The ATC forward link can be based on an existing or
developing CDMA technology (e.g., IS-95, Wideband-CDMA, etc.). The
ATC network return link can also be based on an existing or
developing CDMA technology provided that the radiotelephone's
output is gated to cease transmissions for approximately 3 msec
once every T msec. In some embodiments, T will be greater than or
equal to 6 msec.
This gating may not be needed for ATC return link carriers at
approximately 1550 MHz or below. This gating can reduce or minimize
out-of-band interference (desensitization) effects for GPS
receivers in the vicinity of an ATC. To increase the benefit to
GPS, the gating between all radiotelephones over an entire ATC
service area can be substantially synchronized. Additional benefit
to GPS may be derived from system-wide synchronization of gating.
The ATCs can instruct all active radiotelephones regarding the
gating epoch. All ATCs can be mutually synchronized via GPS.
Filters for Combined Radiotelephone/GPS Terminals
As was described above, some embodiments of the present invention
may employ a Space-Based Network (SBN) and an Ancillary Terrestrial
Network (ATN) that both communicate with a plurality of
radiotelephones using satellite radiotelephone frequencies. The SBN
may include one or more Space-Based Components (SBC) and one or
more satellite gateways. The ATN may include a plurality of
Ancillary Terrestrial Components (ATC). In some embodiments, the
SBN and the ATN may operate at L-band (1525-1559 MHz forward
service link, and 1626.5-1660.5 MHz return service link). Moreover,
in some embodiments, the radiotelephones may be similar to
conventional handheld cellular/PCS-type terminals that are capable
of voice and/or packet data services. In some embodiments,
terrestrial reuse of at least some of the mobile satellite
frequency spectrum can allow the SBN to serve low density areas
that may be impractical and/or uneconomical to serve via
conventional terrestrial networks, while allowing the ATN to serve
pockets of densely populated areas that may only be effectively
served terrestrially. The radiotelephones can be attractive,
feature-rich and/or low cost, similar to conventional
cellular/PCS-type terminals that are offered by terrestrial-only
operators. Moreover, by operating the SBN and ATN modes over the
same frequency band, component count in the radiotelephones, for
example in the front end radio frequency (RF) section, may be
reduced. In particular, in some embodiments, the same frequency
synthesizer, RF filters, low noise amplifiers, power amplifiers and
antenna elements may be used for terrestrial and satellite
communications.
In some embodiments, the radiotelephones also can include a GPS
signal receiver and/or GPS signal processor. Moreover, as was shown
in FIG. 3, since the radiotelephone forward and return links and
the GPS band occupy nearby portions of the satellite frequency
spectrum, the GPS signal receiver that may be built into the
radiotelephone also may share common components with the
radiotelephone.
Embodiments of the present invention that will now be described can
reduce or eliminate performance degradation that may take place in
a radiotelephone that is combined with a GPS signal receiver. In
particular, referring to FIG. 13, an antenna 140a of an ancillary
terrestrial component is illustrated. In some embodiments of the
invention, radiation by the antenna 140a may be directed downward
to below the horizon, to provide more useful radiation to
radiotelephones 1320. Radiotelephones 1320 may be similar to the
radiotelephones 120 that were described above, except that a GPS
signal receiver and/or GPS signal processor also may be included,
as will be described below.
Thus, referring to FIG. 13, the asymmetrical radiation pattern of
the antenna 140a generates enhanced radiation below the horizon
1330, and suppressed or reduced radiation above the horizon 1330.
This pattern of enhanced radiation below the horizon and suppressed
radiation above the horizon may be obtained by antenna down-tilt,
and/or antenna beam forming, and/or other techniques that can
provide asymmetrical radiation patterns relative to the horizon, as
shown in the polar chart of FIG. 14, and in the gain versus
elevation graph of FIG. 15. In FIG. 14, the horizon is indicated by
the line 1330, and the antenna radiation pattern boresight is
directed along the line extending from the origin to 0 degrees.
Below the horizon is indicated in the general direction of
-90.degree. to the left of line 1330, and above the horizon is
indicated in the general direction of +90.degree. to the right of
line 1330.
As shown in FIG. 14, antenna pattern side lobes may be suppressed
or reduced above the horizon and enhanced below the horizon. Stated
differently, the radiation pattern of the antenna 140a is directed
downward to enhance the amount of radiation that is received by a
radiotelephone 1320 and/or to reduce the amount of airborne
radiation which may potentially interfere with airborne
communications systems.
It has been found, according to some embodiments of the present
invention, that the enhanced downward directed radiation that is
provided by the antenna 140a may impact the GPS signal receiver
and/or GPS signal processing that may be included in radiotelephone
1320. Accordingly, in some embodiments of the invention, a GPS mode
filter may be provided in the front end of the radiotelephone 1320
preferably before a Low Noise Amplifier (LNA) that provides
amplification to the GPS signal.
FIG. 16 is a block diagram of a radiotelephone 1320 that includes a
GPS signal receiver and/or GPS signal processor according to some
embodiments of the present invention. In these embodiments, a
common antenna 1410 may be provided for satellite and terrestrial
transmission and reception and for GPS signal reception. It will be
understood, however, that the antenna 1410 also may include
elements that are used only for satellite, terrestrial or GPS. As
also shown in FIG. 16, a single satellite/terrestrial/GPS front end
1420 may be provided for radio frequency processing of the
satellite, terrestrial and GPS signals. It also will be understood
that, although a single front end may be provided to reduce
component count, there may be some components that are provided
exclusively for terrestrial, satellite and/or GPS use. As also
shown in FIG. 16, a single satellite/terrestrial/GPS signal
processor 1430 also may be provided. It will be understood,
however, that some separate signal processing portions also may be
provided to allow for unique requirements for satellite,
terrestrial and/or GPS processing.
Still referring to FIG. 16, a GPS mode filter 1440 may be provided.
This filter 1440 may be a high pass, bandpass, notch and/or other
filter that can attenuate selected frequencies. According to some
embodiments of the present invention, the GPS mode filter 1440 is a
high pass filter that is operative to selectively suppress energy
at and/or below (1575.42-.DELTA.) MHz, where
0<.DELTA..ltoreq.16.42 MHz. This high pass filter may thereby
prevent, reduce or minimize the effect of the radiation of the
antenna 140a when radiotelephone 1320 is receiving GPS signals.
Stated in other words, the GPS mode filter may be operative to
selectively suppress energy at frequencies at and/or below
(1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42 MHz, and to
selectively pass energy at frequencies greater than
(1575.42-.DELTA.) MHz.
In particular, referring to FIG. 17, a spectrum diagram that
illustrates satellite L-band frequency allocations is shown. As
shown, the cellular satellite forward link may be provided at
frequencies between 1525 MHz and 1559 MHz. The GPS/GLONASS band may
be between 1559 MHz and 1605 MHz. In particular, the GPS L1
frequency that carries the navigation message and the code signals
for civilian GPS may be centered at 1575.42 MHz, and civilian GPS
signals may be provided at 1575.42 MHz.+-.1 MHz. As shown in FIG.
17, the GPS mode filter 1440 such as a high pass filter may have a
high pass filter slope that allows the L1 frequency to pass
substantially unattenuated, but that attenuates frequencies that
are lower than the L1 frequency. It will be understood that the
slope, cut off point and/or bandwidth of the filter 1440 may be
designed based on the particular environment in which the
radiotelephone 1320 is being operated, the RF characteristics of
the front end, the RF characteristics of the antenna 1410 and/or
other factors. In some embodiments, the energy is suppressed by at
least 10 dB by filter 1440 for at least one value of .DELTA.. The
design of filters is well known to those having skill in the art
and need not be described further herein.
Filters according to some embodiments of the present invention
thereby can allow a combined radiotelephone/GPS terminal to
effectively receive and/or process GPS signals while eliminating,
minimizing or reducing the impact to the front end and/or other
stages of the combined radiotelephone/GPS terminal due to the
enhanced terrestrial radiation that may be provided by the
ancillary terrestrial network.
Additional radiotelephones according to other embodiments of the
present invention are illustrated in FIGS. 18 and 19. As shown in
FIG. 18, a radiotelephone 1320' according to additional embodiments
of the present invention can include a single
satellite/terrestrial/GPS antenna 1803, a single
satellite/terrestrial/GPS front end 1805, a GPS mode filter 1807, a
single satellite/terrestrial/GPS signal processor 1809, and a user
interface 1811. While a single antenna, a single front end, and a
single signal processor are shown as providing both GPS and
satellite/terrestrial communications functionalities, each of these
elements may include portions thereof dedicated to GPS
functionality and/or satellite/terrestrial communications
functionality.
The radio front end 1805 can be configured to provide wireless
radiotelephone communications with a space-based component using
satellite radiotelephone frequencies and to provide wireless
radiotelephone communications with an ancillary terrestrial
component using at least one of the satellite radiotelephone
frequencies. The radio front end can be further configured to
receive global positioning satellite (GPS) signals from a plurality
of global positioning satellites. The signal processor 1809 can be
configured to determine a measure of location of the radiotelephone
using GPS signals received at the radio front end when providing
GPS mode operations and to process communications that are received
at and/or transmitted by the radio front end when providing
wireless radiotelephone communications.
Multiple antenna segments may be provided, and/or the antenna 1803
may include elements that are used only for satellite, terrestrial,
or GPS. In addition, by operating the SBN and ATN modes over the
same frequency bands, component count in the radiotelephones, for
example in the front end 1805, may be reduced. In particular, in
some embodiments, the same frequency synthesizer, RF filters, low
noise amplifiers, power amplifiers and antenna elements may be used
for terrestrial and satellite communications, and/or some
components may be provided exclusively for terrestrial, satellite,
or GPS use. In addition, the signal processor may include different
portions of hardware and/or software directed to the different
functionalities and/or different signal processing tasks.
When the radiotelephone is operating to provide GPS mode
operations, GPS signals are received through the antenna 1803, the
single satellite/terrestrial/GPS front end 1805, and the GPS mode
filter 1807, and/or provided to the satellite/terrestrial/GPS
signal processor 1809. The single satellite/terrestrial/GPS signal
processor 1809 processes the GPS signals and may provide a global
positioning output measure at the user interface 1811. The user
interface 1811, for example, can include a liquid crystal display
that can provide a visual indication of position such as a map
and/or an alphanumeric indication of location such as a longitude
and latitude. The user interface 1811 can also include a speaker
and microphone for radiotelephone communications, and/or a user
input such as a keypad or a touch sensitive screen.
As discussed above with respect to the GPS mode filter 1440 of FIG.
16, the GPS mode filter 1807 may be a high pass, bandpass, notch
and/or other filter that can attenuate selected frequencies. As
discussed above with respect to FIGS. 3 and 17, cellular satellite
forward service links (down link frequency band) may be provided at
frequencies between 1525 MHz and 1559 MHz, cellular satellite
return service links (uplink frequency band) can be provided at
frequencies between 1626.5 MHz and 1660.5 MHz, and the GPS/GLONASS
band can be provided between 1559 MHz and 1605 MHz. More
particularly, the GPS L1 frequency that carries the navigation
message and code signals for civilian GPS use is substantially
located at 1575.42+/-1 MHz. Accordingly, the GPS mode filter 1807
can be a high pass filter having a high pass filter slope that
allows the L1 frequency to pass relatively unattenuated, but that
selectively attenuates frequencies that are lower than the L1
frequency. It will be understood that the slope, cut off point
and/or bandwidth of the filter 1807 may be designed based on a
particular environment in which the radiotelephone 1320' is being
operated, the RF characteristics of the front end, the RF
characteristics of the antenna 1803, and/or other factors.
Accordingly, the GPS mode filter 1807 can be configured to
selectively suppress energy at and/or below (1575.42-.DELTA.) MHz,
where 0<.DELTA.<16.42 MHz. Moreover, the GPS mode filter can
be configured to selectively suppress at least 10 dB of energy at
and/or below (1575.42-.DELTA.) MHz. The GPS mode filter can be
further configured to selectively suppress at least 10 dB of energy
at frequencies of (1575.42-.DELTA.) MHz and lower.
According to some embodiments of the present invention, the GPS
mode filter 1807 can be operative to selectively pass energy having
a frequency of 1575.42+/-1 MHz and to selectively attenuate energy
having a frequency of less than or equal to (1575.42-.DELTA.) MHz,
where 0<.DELTA.<16.42 MHz. More particularly, the energy can
be suppressed by at least 10 dB for frequencies less than or equal
to (1575.42-.DELTA.) MHz, and .DELTA. can be greater than at least
1 MHz. Accordingly, GPS signals can be received while eliminating,
minimizing, and/or reducing the impact to the front end and other
sections of the combined satellite/terrestrial/GPS radiotelephone
due to enhanced radiation in the cellular satellite forward link
frequency band that may be provided by the ancillary terrestrial
network.
Processing of GPS signals can be suppressed at the front end 1805
and/or at the signal processor 1809 when actively providing
satellite/terrestrial communications. The bidirectional coupling
between the common satellite/terrestrial/GPS front end 1805 and the
satellite/terrestrial/GPS signal processor 1809 facilitates two way
communications such as a radiotelephone conversation and/or sending
and receiving e-mails or other data, so that wireless
radiotelephone communications are not subjected to the GPS mode
filter.
The common satellite/terrestrial/GPS front end 1805 can be coupled
to a communications input or satellite/terrestrial/GPS signal
processor 1809 to provide communications system signal monitoring
during GPS operations, such as control signals. Accordingly, an
incoming call page can be received at the front end 1805 and
processed at signal processor 1809 during GPS operations. In the
alternative, a switch may be provided to select either GPS signals
or communications system signals for coupling to and processing at
the satellite/terrestrial/GPS signal processor. Moreover, the GPS
mode filter can be implemented as an analog and/or digital
filter.
As shown in the example of FIG. 19, a radiotelephone 1320''
according to yet additional embodiments of the present invention
can include a front end 1925 with a common satellite/terrestrial
front end portion 1927 and a GPS front end portion 1929
respectively coupled to a satellite/terrestrial antenna 1921 and a
GPS antenna 1923. The radiotelephone 1320'' can also include a
signal processor 1933 having a GPS signal processor portion 1937
and a satellite/terrestrial processor portion 1935, and the signal
processor 1933 can be coupled with a user interface 1939. A GPS
mode filter 1931 can be inserted preferably between the GPS antenna
1923 and a GPS Low Noise Amplifier (LNA) of the GPS front end 1929.
The satellite/terrestrial front end portion 1927 can be directly
coupled with the satellite/terrestrial signal processor portion
1935.
The GPS front end portion 1929 can be configured to receive global
positioning satellite (GPS) signals from a plurality of global
positioning satellites. The common terrestrial/satellite front end
portion 1927 can be configured to provide wireless radiotelephone
communications with a space-based component using satellite
radiotelephone frequencies and to provide wireless radiotelephone
communications with an ancillary terrestrial component using at
least one of the satellite radiotelephone frequencies. The GPS
signal processor portion 1937 can be configured to determine a
measure of location of the radiotelephone using GPS signals
received at the GPS front end portion 1929 when providing GPS mode
operations. The common terrestrial/satellite signal processor
portion 1935 can be configured to process communications that are
received at and/or transmitted from the common
terrestrial/satellite front end portion 1927 when providing
wireless radiotelephone communications.
The GPS signal processor 1937 may communicate bidirectionally with
the terrestrial/satellite signal processor 1935 to receive and/or
relay information from/to the terrestrial/satellite signal
processor 1935, and/or the ATN, and/or the SBN. Such information
may indicate points in time where measure(s) of position of
radiotelephone 1320'' may be determined by GPS signal processor
1937, or value(s) of position measures of radiotelephone 1320''
that have been determined by GPS signal processor 1937 and/or being
relayed to the SBN and/or the ATN.
The radiotelephone 1320'' of FIG. 19 is similar to the
radiotelephone 1320' of FIG. 18 with the exception that FIG. 19
shows separate GPS and terrestrial/satellite portions of the front
end 1925 and the signal processor 1933, and separate GPS and
satellite/terrestrial antennas 1923 and 1921. By operating the SBN
and ATN modes over the same frequency band, component count in the
radiotelephones, for example in the common terrestrial/satellite
front end portion 1927, may be reduced. In particular, in some
embodiments, the same frequency synthesizer, RF filters, low noise
amplifiers, power amplifiers and antenna elements may be used for
terrestrial and satellite communications.
The GPS front end portion 1929 and the common terrestrial/satellite
front end portion 1927 may share one or more common components, and
the two front end portions may have separate couplings to a single
antenna instead of two separate antennas as shown. As shown, there
may be some components that are provided exclusively for
terrestrial, satellite, or GPS use. The GPS signal processor
portion 1937 and the satellite/terrestrial signal processor portion
1935 may have separate hardware and/or software portions and/or
operate in whole or in part in different physical portions of one
or more processors.
When the radiotelephone 1320'' is operating to provide GPS mode
operations, GPS signals can be received through the antenna 1923
and the GPS front end portion 1929 and provided to the GPS signal
processor portion 1937 through a coupling with the GPS mode filter
1931. The GPS signal processor portion 1937 can process the GPS
signals and may provide a global positioning output at the user
interface 1939 in response to a user command and/or information
received from the SBN and/or ATN. The user interface 1939, for
example, can include a liquid crystal display that can provide a
visual indication of position such as a map and/or an alphanumeric
indication of location such as a longitude and latitude. The user
interface can also include a speaker and microphone for
radiotelephone communications, and/or a user input such as a keypad
or a touch sensitive screen.
As discussed above with respect to the GPS mode filter 1440 of FIG.
16 and the GPS mode filter 1807 of FIG. 18, the GPS mode filter
1931 may be a high pass, bandpass, notch and/or other filter that
can attenuate selected frequencies. As discussed above with respect
to FIGS. 3 and 17, cellular satellite and ATC forward links may be
provided at frequencies between 1525 MHz and 1559 MHz, and the
GPS/GLONASS band is provided between 1559 MHz and 1605 MHz. More
particularly, the GPS L1 frequency that carries the navigation
message and code signals for civilian GPS use is located at
1575.42+/-1 MHz. Accordingly, the GPS mode filter 1931 can be a
high pass filter having a high pass filter slope that allows the L1
frequency to pass relatively unattenuated, but that attenuates
frequencies that are lower than the L1 frequency. It will be
understood that the slope, cut off frequency and/or bandwidth of
the filter 1931 may be designed based on a particular environment
in which the radiotelephone 1320'' is being operated, the RF
characteristics of the front end, the RF characteristics of the
antenna 1923, and/or other factors such as radiation patterns of
ATC antennas.
Accordingly, the GPS mode filter 1931 can be configured to
selectively suppress energy at frequencies at and/or below
(1575.42-.DELTA.) MHz, where 0<.DELTA.<16.42 MHz. Moreover,
the GPS mode filter can be configured to selectively suppress at
least 10 dB of energy at frequencies at and/or below
(1575.42-.DELTA.) MHz. The GPS mode filter can be further
configured to selectively suppress at least 10 dB of energy at
frequencies of (1575.42-.DELTA.) MHz and lower.
According to some embodiments of the present invention, the GPS
mode filter 1931 can be operative to substantially pass energy
having a frequency of 1575.42+/-1 MHz and to selectively attenuate
energy having a frequency of less than (1575.42-.DELTA.) MHz, where
0<.DELTA.<16.42 MHz. More particularly, the energy can be
selectively suppressed by at least 10 dB for frequencies of
(1575.42-.DELTA.) MHz and lower, and .DELTA. can be greater than at
least 1 MHz. Accordingly, GPS signals can be received while
eliminating, minimizing, or reducing the impact to the front end of
the combined satellite/terrestrial/GPS radiotelephone due to
enhanced radiation in the cellular satellite forward link frequency
band that may be provided by the ancillary terrestrial network.
Processing of GPS mode signals can be suppressed at the GPS front
end portion 1929 and/or the GPS signal processor portion 1937 when
actively providing satellite/terrestrial communications and more
particularly when transmitting satellite/terrestrial communications
from the radiotelephone 1320''. The bi-directional coupling between
the satellite/terrestrial front end portion 1927 and the
terrestrial/satellite signal processor 1935 may facilitate two way
communications such as a radiotelephone conversation and/or sending
and receiving e-mails or other data, so that wireless
radiotelephone communications are not subjected to the GPS mode
filter.
Moreover, the satellite/terrestrial front end portion 1927 and the
satellite/terrestrial signal processor portion 1935 may provide
reception of communications system signals, such as control signals
received over control channels, during GPS operations. Accordingly,
an incoming call page can be received at the terrestrial/satellite
front end 1927 and processed at the terrestrial/satellite signal
processor 1935 during GPS operations, for example, to provide an
indication of an incoming call.
According to additional embodiments of the present invention, a
radiotelephone can include a radio front end configured to provide
wireless radiotelephone communications with a space-based component
using satellite radiotelephone frequencies and to provide wireless
radiotelephone communications with a plurality of ancillary
terrestrial components using at least one of the satellite
radiotelephone frequencies. The radio front end can also be
configured to receive global positioning satellite (GPS) signals
from a plurality of global positioning satellites. During GPS mode
operations, received energy can be selectivley suppressed at
frequencies at and/or below (1575.42-.DELTA.) MHz, where
0<.DELTA..ltoreq.16.42 MHz, and a measure of location of the
radiotelephone can be determined using the GPS signals having
suppressed energy at and/or below (1575.42-.DELTA.) MHz. During
wireless radiotelephone communications, communications received at
and transmitted from the radio front end can be processed. During
wireless radiotelephone communications, the wireless radiotelephone
communications can be processed without significantly suppressing
energy of the communications at and/or below (1575.42-.DELTA.)
MHz.
During GPS mode operations, selectively suppressing energy at
and/or below (1575.42-.DELTA.) MHz can include selectively
suppressing at least 10 dB of energy at (1575.42-.DELTA.) MHz and
at frequencies less than (1575.42-.DELTA.) MHz. During wireless
radiotelephone communications, processing of GPS signals can be
suppressed when actively providing radiotelephone communications
with the space-based component and/or one of the ancillary
terrestrial components.
The satellite radiotelephone frequencies can include a satellite
downlink frequency band and a satellite uplink frequency hand and
GPS signals can be transmitted from GPS satellites over a GPS
frequency band between the satellite downlink and uplink frequency
bands. More particularly, the satellite downlink frequency band can
include frequencies between 1525 MHz and 1559 MHz, and the
satellite uplink frequency band can include frequencies between
1626.5 MHz and 1660.5 MHz. The GPS frequency band can include
frequencies between 1559 MHz and 1605 MHz. Moreover, when
suppressing energy at and/or below (1575.42-.DELTA.) MHz, .DELTA.
can be greater than at least 1 MHz. In addition, an incoming call
page can be received during GPS mode operations, and the incoming
call page can be processed during GPS operations.
FIG. 20 illustrates radiotelephones according to yet additional
embodiments of the present invention. As shown, a radiotelephone
2011 can include a front end 2015, a signal processor 2017, a GPS
antenna 2005, a terrestrial/satellite antenna 2007, and a user
interface 2019. More particularly, the front end 2015 can include a
GPS front end portion 2021 and a terrestrial/satellite front end
portion 2023, and the signal processor 2017 can include a GPS
signal processor portion 2025 and a terrestrial/satellite signal
processor portion 2027.
According to embodiments illustrated in FIG. 20, a first low noise
amplifier 2031 can be provided in the GPS front end portion 2021,
and a second low noise amplifier 2033 can be provided in the
terrestrial/satellite front end portion 2023. Accordingly, GPS
signals can be received through GPS antenna 2005, the GPS filter
2022, and the GPS low noise amplifier 2031, and provided to the GPS
signal processor portion 2025 of the signal processor 2017. The GPS
signal processor portion 2025 can thus generate a measure of
location of the radiotelephone 2011, and a measure of location can
be provided to a user of the radiotelephone via user interface
2019. A coupling between the GPS signal processor portion 2025 and
the terrestrial/satellite signal processor portion 2027 can also be
provided so that a measure of location of the radiotelephone can be
transmitted to an SBN and/or ATN and/or so that commands or other
information from an SBN and/or ATN can be provided to the GPS
signal processor portion 2025.
During GPS mode operations, the GPS filter 2022 of GPS front end
portion 2021 can selectively suppress energy received at
frequencies at and/or below (1575.42-.DELTA.) MHz, where
0<.DELTA..ltoreq.16.42 MHz, and a measure of location of the
radiotelephone can be determined using the GPS signals having
suppressed energy at and/or below (1575.42-.DELTA.) MHz. During GPS
mode operations, selectively suppressing energy at and/or below
(1575.42-.DELTA.) MHz can include selectively suppressing at least
10 dB of energy at (1575.42-.DELTA.) MHz and at frequencies less
than (1575.42-.DELTA.) MHz. During wireless radiotelephone
communications, processing of GPS signals can be suppressed when
actively providing radiotelephone communications (including
transmissions) with the space-based component and/or one of the
ancillary terrestrial components. The use of separate low noise
amplifiers, however, may allow the radiotelephone to receive
signals from an SBN and/or ATN (such as control signals including
call pages provided over control channels) during GPS mode
operations.
During wireless radiotelephone communications, communications
received at and/or transmitted from the terrestrial/satellite front
end portion 2023 can be processed. During wireless radiotelephone
communications, the wireless radiotelephone communications can be
processed without significantly suppressing energy of the
communications at and/or below (1575.42-.DELTA.) MHz because the
GPS filter 2022 is not in the receive path for
terrestrial/satellite communications. As shown in FIG. 20, the
terrestrial/satellite front end portion 2023 can include low noise
amplifier 2033, a communications filter 2041, a transmitter 2043,
and a duplexer 2045. The duplexor 2045 can provide coupling between
the antenna 2007, the transmitter 2043, and the communications
filter 2041. It will be understood that the communications filter
2041 may not be required in some embodiments wherein the duplexer
itself provides adequate isolation between the communications
transmitter and receiver. It will also be understood that in some
embodiments where TDMA is the multiple access technique used for
communications signal transmission and reception, the duplexer 2045
may be repliced by a transmit/receive switch.
Accordingly, received radiotelephone communications can be received
through the antenna 2007, the duplexer 2045, the communications
filter 2041, and the low noise amplifier 2033, and provided to the
terrestrial/satellite signal processor portion 2027. Similarly,
transmitted radiotelephone communications from the
terrestrial/satellite signal processor portion 2027 can be provided
to the terrestrial/satellite front end portion 2023, and
transmitted through the transmitter 2043, the duplexer 2045, and
the antenna 2007. As discussed above, the GPS front end portion
2021 and the GPS signal processor portion 2025 may provide GPS mode
operations while signals are received through the
terrestrial/satellite front end portion 2023 and the
terrestrial/satellite signal processor portion 2027. It may be
desirable, however, to suspend GPS mode operations while
transmitting from the terrestrial/satellite front end portion
2015.
While two antennas are illustrated in FIG. 20, more or fewer
antennas may be used according to additional embodiments of the
present invention. For example, a single antenna may be used for
both GPS and radiotelephone operations with one or more duplexers
being used to couple the single antenna to respective filters and
antennas. Alternately, separate antennas may be provided for GPS
reception, radiotelephone reception, and radiotelephone
transmission.
FIG. 21 illustrates radiotelephones according to still additional
embodiments of the present invention. As shown, a radiotelephone
3011 can include a front end 3015, a signal processor 3017, a GPS
antenna 3005, a terrestrial/satellite communications signal antenna
3007, and a user interface 3019. According to embodiments
illustrated in FIG. 21, the front end 3015 can include a GPS filter
3021, a radiotelephone communications filter 3041, a duplexer 3045,
and a transmitter 3043. In addition, a switch 3051 can be used to
selectively couple either the GPS filter 3021 or the communications
filter 3041 to a single low noise amplifier 3032. Accordingly, the
radiotelephone 3011 does not receive GPS signals and radiotelephone
signals at the same time.
During GPS operations, the switch 3051 couples the GPS filter 3021
to the low noise amplifier 3032, and decouples the communications
filter 3041 from the low noise amplifier 3032. Accordingly, GPS
signals can be received through GPS antenna 3005, the GPS filter
3021, the switch 3051, and the low noise amplifier 3032, and
provided to the signal processor 3017. The signal processor 3017
can thus generate a measure of location of the radiotelephone 3011,
and a measure of location can be provided to a user of the
radiotelephone via user interface 3019. In addition, a measure of
location of the radiotelephone can be transmitted through
transmitter 3043 to the SBN and/or ATN and/or commands or other
information from the SBN and/or ATN can be provided to the signal
processor 3017.
During GPS mode operations, the GPS filter 3021 of the front end
3015 can selectively suppress energy received at frequencies at
and/or below (1575.42-.DELTA.) MHz, where 0<.DELTA..ltoreq.16.42
MHz, and a measure of location of the radiotelephone can be
determined using the GPS signals having suppressed energy at and/or
below (1575.42-.DELTA.) MHz. During GPS mode operations,
selectively suppressing energy at and/or below (1575.42-.DELTA.)
MHz can include selectively suppressing at least 10 dB of energy at
(1575.42-.DELTA.) MHz and at frequencies less than
(1575.42-.DELTA.) MHz. During wireless radiotelephone
communications, processing of GPS signals can be suppressed because
the switch 3051 will decouple the GPS filter 3021 from the low
noise amplifier 3032.
During wireless radiotelephone communications, communications
received at and/or transmitted from the radiotelephone 3011 can be
processed. During wireless radiotelephone communications, the
wireless radiotelephone communications can be processed without
significantly suppressing energy of the communications at and/or
below (1575.42-.DELTA.) MHz because the GPS filter 3021 is not in
the receive path for terrestrial/satellite communications. As shown
in FIG. 21, radiotelephone communications can be received through
the antenna 3007, duplexer 3045, communications filter 3041, switch
3051, and low noise amplifier 3032, and provided to the signal
processor 3017. Radiotelephone communications from the signal
processor 3017 can be transmitted through the transmitter 3043, the
duplexer 3045, and the antenna 3007. The duplexor 3045 can provide
coupling between the antenna 3007, the transmitter 3043, and the
communications filter 3041.
Accordingly, received radiotelephone communications can be received
through the antenna 3007, the duplexer 3045, the communications
filter 3041, and the low noise amplifier 3032, and provided to the
signal processor 3017. Similarly, transmitted radiotelephone
communications from the signal processor 3017 can be transmitted
through the transmitter 3043, the duplexer 3045, and the antenna
3007. It will be understood that the communications filter 3041 may
not be required in some embodiments wherein the duplexer itself
provides adequate isolation between the communications transmitter
and receiver. It will also be understood that in some embodiments
where TDMA is the multiple access technique used for communications
signal transmission and reception, the duplexer 3045 may be
replaced by a transmit/receive switch.
While two antennas are illustrated in FIG. 21, more or fewer
antennas may be used according to additional embodiments of the
present invention. For example, a single antenna may be used for
both GPS and radiotelephone operations with one or more duplexers
being used to couple the single antenna to respective filters and
antennas. Alternately, separate antennas may be provided for GPS
reception, radiotelephone reception, and radiotelephone
transmission.
In the drawings and specification, there have been disclosed
typical preferred embodiments of the invention and, although
specific terms are employed, they are used in a generic and
descriptive sense only and not for purposes of limitation. While
this invention has been particularly shown and described with
reference to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and
details may be made therein without departing from the spirit and
scope of the invention as defined by the appended claims.
* * * * *
References