U.S. patent application number 11/020981 was filed with the patent office on 2006-06-22 for interoperability between receivers and transmitters in a mobile station.
This patent application is currently assigned to Nokia Corporation. Invention is credited to Marko Leinonen, Jarkko Mykkanen, Juha Valtanen.
Application Number | 20060135083 11/020981 |
Document ID | / |
Family ID | 36596619 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060135083 |
Kind Code |
A1 |
Leinonen; Marko ; et
al. |
June 22, 2006 |
Interoperability between receivers and transmitters in a mobile
station
Abstract
Techniques are disclosed for improving the interoperability of
transmitters and receivers in a mobile station. Certain exemplary
techniques involve performing filtering in a transmitter in
response to a notification that a receiver is able to receive a
reception frequency band. Other exemplary techniques involve
changing one or more inputs of one or more devices in a receiver in
response to a transmission by a transmitter. Still other exemplary
techniques are disclosed.
Inventors: |
Leinonen; Marko; (Oulu,
FI) ; Valtanen; Juha; (Oulu, FI) ; Mykkanen;
Jarkko; (Oulu, FI) |
Correspondence
Address: |
HARRINGTON & SMITH, LLP
4 RESEARCH DRIVE
SHELTON
CT
06484-6212
US
|
Assignee: |
Nokia Corporation
|
Family ID: |
36596619 |
Appl. No.: |
11/020981 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
455/78 ;
455/553.1; 455/73 |
Current CPC
Class: |
H04B 1/0064 20130101;
H04B 1/0057 20130101; H04B 1/006 20130101 |
Class at
Publication: |
455/078 ;
455/073; 455/553.1 |
International
Class: |
H04B 1/38 20060101
H04B001/38; H04B 1/44 20060101 H04B001/44; H04B 17/00 20060101
H04B017/00; H04M 1/00 20060101 H04M001/00 |
Claims
1. A mobile station comprising: a first antenna; at least one
second antenna; a receiver coupled to the first antenna, the
receiver comprising first control logic adapted to generate a
notification of the receiver being able to receive a reception
frequency band, a transmitter coupled to the at least one second
antenna and the receiver, the transmitter communicating radio
frequency (RF) signals in a selected one of at least one
transmission frequency bands over an RF transmit path to the at
least one second antenna, the transmitter comprising: second
control logic; at least one filter; and at least one switch coupled
to the RF transmit path, the at least one filter, and the control
logic, the at least one switch adapted to modify the RF transmit
path to couple a given one of the at least one filters to or
decouple the given filter from the RF transmit path, wherein the
second control logic is responsive to the notification to cause the
at least one switch to modify the RF transmit path to couple the
given filter to the RF transmit path.
2. The mobile station of claim 1, further comprising a display
device coupled to the receiver and adapted to display at least
information received from the receiver.
3. The mobile station of claim 1, wherein: the first control
circuitry is responsive to the notification to generate at least
one control signal; and the at least one switch is coupled to the
at least one control signal and is responsive to the at least one
control signal to modify the RF transmit path to couple the given
filter to or decouple the given filter from the RF transmit
path.
4. The mobile station of claim 3, wherein: the at least one switch
comprises a first switch, the first switch coupled to an antenna
coupling in the RF transmit path and intermediate the antenna
coupling and the at least one filter, the first switch responsive
to one of the at least one control signals to couple the at least
one filter to or decouple the at least one filter from the antenna
coupling.
5. The mobile station of claim 4, wherein: the at least one control
signal comprises first and second control signals; the at least one
filter comprises two filters; the at least one switch comprises a
second switch coupled to and intermediate the first switch and the
two filters, the second switch responsive to the second control
signal to couple one of the two filters to an output of the second
switch; and the first switch is responsive to the first control
signal to couple the output of the second switch to or decouple the
output of the second switch from the antenna coupling.
6. The mobile station of claim 5, wherein: the at least one
transmission frequency band comprises first and second transmission
frequency bands; the two filters comprise first and second filters,
the first filter corresponding to the first transmission frequency
band and the second filter corresponding to the second transmission
frequency band; the control logic is responsive to the transmitter
being in a transmission mode to cause, by using the first control
signal, the first switch to couple the output of the second switch
to the antenna coupling; and the control logic is responsive to
which of the first and second transmission frequency bands is to be
used for transmission to cause, by using the second control signal,
the second switch to couple the first filter to the output of the
second switch when the first transmission frequency band is to be
used for transmission and to couple the second filter to the output
of the second switch when the second transmission frequency band is
to be used for transmission.
7. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises first and second transmission
frequency bands; the at least one filter comprises first and second
filters, the first filter corresponding to the first transmission
frequency band and the second filter corresponding to the second
transmission frequency band; and the control logic is responsive to
which of the first and second transmission frequency bands is to be
used for transmission to cause the at least one switch to couple
the first filter to the RF transmit path when the first
transmission frequency band is to be used for transmission and to
couple the second filter to the RF transmit path when the second
transmission frequency band is to be used for transmission.
8. The mobile station of claim 7, wherein the at least one switch
comprises a single switch, the single switch comprising three
positions and an output, a first position coupling the first filter
to the output, a second position coupling the second filter to the
output, and a third position coupling a not connected terminal to
the output.
9. The mobile station of claim 7, wherein: the second control logic
is adapted to generate first and second control signals; the at
least one switch comprises first and second switches; the first
switch is coupled to the first filter and is responsive to the
first control signal to couple the first filter to the RF transmit
path; and the second switch is coupled to the second filter and is
responsive to the second control signal to couple the second filter
to the RF transmit path.
10. The mobile station of claim 7, wherein: the transmitter
comprises a power amplifier; the at least one switch comprises
first and second switches, each of the first and second switches
having a single terminal and first, second, and third terminals;
the single terminal of the first switch is coupled to the power
amplifier; the first terminal of the first switch is coupled to an
input of the first filter, and the output of the first filter is
coupled to the first terminal of the second switch; the second
terminal of the first switch is coupled to the second terminal of
the second switch; the third terminal of the first switch is
coupled to an input of the second filter, and an output of the
second filter is coupled to the third terminal of the second
switch; and the single terminal of the second switch is coupled to
the at least one second antenna
11. The mobile station of claim 7, wherein: the at least one second
antenna comprises two given antennas; the transmitter comprises a
power amplifier; the at least one switch comprises first and second
switches, the first switch having a single terminal and first,
second, and third terminals, the second switch having a single
terminal and first and second terminals; the single terminal of the
first switch is coupled to the power amplifier; the first terminal
of the first switch is coupled to an input of the first filter, and
the output of the first filter is coupled to the first terminal of
the second switch; the second terminal of the first switch is
coupled to the second terminal of the second switch; the third
terminal of the first switch is coupled to an input of the second
filter, and an output of the second filter is coupled to one of the
given antennas; and the single terminal of the second switch is
coupled to the other of the given antennas.
12. The mobile station of claim 7, wherein: the at least one second
antenna comprises three given antennas; the transmitter comprises a
power amplifier; the at least one switch comprises a given switch
having a single terminal and first, second, and third terminals;
the single terminal of the given switch is coupled to the power
amplifier; the first terminal of the given switch is coupled to an
input of the first filter, and the output of the first filter is
coupled to a first of the given antennas; the second terminal of
the given switch is coupled to a second of the given antennas; and
the third terminal of the first switch is coupled to an input of
the second filter, and an output of the second filter is coupled to
a third of the given antennas.
13. The mobile station of claim 1, wherein: the transmitter further
comprises at least one radio frequency (RF) device adapted to
create the RF signals in the selected one of the at least one
transmission frequency bands; and the RF transmit path comprises a
path from the at least one RF device to the at least one second
antenna.
14. The mobile station of claim 13, wherein the second control
logic is part of the at least one switch.
15. The mobile station of claim 13, wherein the second control
logic is part of the at least one RF device and is adapted to cause
the at least one RF device to communicate information through the
RF transmit path to the at least one second antenna.
16. The mobile station of claim 13, wherein: the transmitter
further comprises first and second buses from the at least one RF
device to the at least one switch; the at least one RF device is
further adapted to create and communicate first RF signals defined
by a first communication protocol over the first bus and second RF
signals defined by a second communication protocol over the second
bus, the first RF signals defined by the first communication
protocol being the RF signals in a selected one of the at least one
transmission frequency bands; the transmitter further comprises
first and second power amplifiers and at least one duplex filter,
each of the first and second power amplifiers coupled to the at
least one second antenna, the second power amplifier coupled to the
at least one second antenna through the at least one duplex filter;
the at least one switch is coupled to the first and second buses
and is intermediate the at least one RF device and the at least one
duplex filter, the at least one switch adapted to couple the first
bus to the second power amplifier, thereby coupling the at least
one duplex filter to the RF transmit path for the first RF signals,
and to couple the first bus to the first power amplifier and the
second bus to the second power amplifier, thereby decoupling the
duplex filter from the RF transmit path for the first RF
signals.
17. The mobile station of claim 16, wherein the at least one switch
comprises first and second switches, the first switch having inputs
coupled to the first and second buses and an output coupled to an
input of the second switch, the second switch having a first output
coupled to the first power amplifier and a second output coupled to
the second power amplifier.
18. The mobile station of claim 16, wherein: the control logic is
adapted to create two control signals; and the at least one switch
is responsive to the two control signals to couple the first bus to
the second power amplifier when the two control signals are in a
first state, to couple the first bus to the first power amplifier
when the two control signals are in a second state, and to couple
the second bus to the second power amplifier when the two control
signals are in a third state.
19. The mobile station of claim 16, wherein: the first
communication protocol is a global system for mobile communications
(GSM) protocol; and the second communication protocol is a code
division multiple access (CDMA) protocol.
20. The mobile station of claim 16, wherein: the at least one
transmission frequency band is defined by the first protocol to
comprise first and second transmission frequency bands; the second
protocol defines RF signals using the first and second transmission
frequency bands; the at least one duplex filter comprises a first
duplex filter corresponding to the first transmission frequency
band and a second filter corresponding to the second transmission
frequency band; and the second power amplifier is adapted to route
the first transmission frequency band to the first duplex filter
and the second transmission frequency band to the second duplex
filter.
21. The mobile station of claim 16, wherein: the at least one
second antenna comprises two given antennas, wherein one given
antenna is coupled to the first power amplifier, and the other
given antenna is coupled to the at least one duplex filter.
22. The mobile station of claim 16, wherein: the at least one
second antenna comprises a single antenna coupled to both the first
and second power amplifiers.
23. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises one or more of an 824 to 849
megahertz (MHz) frequency band and an 1850 to 1910 MHz frequency
band; and the reception frequency band comprises a 1670 to 1675 MHz
frequency band.
24. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises a 824 to 849 megahertz (MHz)
frequency band and a 1850 to 1910 MHz frequency band; the reception
frequency band comprises a 1670 to 1675 MHz frequency band; the at
least one filter comprises a first filter to filter at least one
harmonic caused by transmitting the 824 to 849 MHz frequency band
and a second filter to filter wideband noise caused by transmitting
the 1850 to 1910 MHZ frequency band.
25. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises one or more of a 880 to 915
megahertz (MHz) frequency band, a 1710 to 1785 MHz frequency band,
and a 1920 to 1980 MHz frequency band; and the reception frequency
band comprises a 470 to 702 MHz frequency band.
26. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises one or more of a 824 to 849
megahertz (MHz) frequency band and a 1850 to 1910 MHz frequency
band; and the reception frequency band comprises a 1670 to 1675 MHz
frequency band.
27. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a global system for mobile communications
(GSM) standard; and the reception frequency band comprises a
reception frequency band defined by a digital video broadcasting
handheld (DVB-H) standard.
28. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a code division multiple access (CDMA)
standard; and the reception frequency band comprises a reception
frequency band defined by a digital video broadcasting handheld
(DVB-H) standard.
29. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a wideband code division multiple access
(WCDMA) standard; and the reception frequency band comprises a
reception frequency band defined by a digital video broadcasting
handheld (DVB-H) standard.
30. The mobile station of claim 1, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a CDMAOne or CDMA2000 standard; and the
reception frequency band comprises a reception frequency band
defined by a digital video broadcasting handheld (DVB-H)
standard.
31. The mobile station of claim 1, wherein the transmitter further
comprises a front end module (FEM), in the RF transmit path,
comprising a power amplifier, and wherein the control logic is
further responsive to the notification to adjust biasing of the
power amplifier.
32. The mobile station of claim 1, wherein the first control logic
is adapted to generate a notification of the receiver being able to
receive a reception frequency band when one or more of the
following is true: the receiver is coupled to the transmitter; the
receiver is in a reception mode; and the receiver is receiving
information in the reception frequency band.
33. In a mobile station comprising a first antenna and at least one
second antenna, a method for operating a transmitter coupled to the
at least one second antenna in combination with a receiver coupled
to the first antenna, comprising: generating a notification of the
receiver being able to receive a reception frequency band from the
first antenna; modifying, in response to the notification, a radio
frequency (RF) transmit path to couple a given one of at least one
filters to or decouple the given filter from the RF transmit path;
and transmitting information in a selected one of at least one
transmission frequency bands and through the modified RF transmit
path to the at least one second antenna.
34. A signal bearing medium comprising a program of
machine-readable instructions executable by an apparatus to perform
operations for operating a transmitter coupled to at least one
second antenna in combination with a receiver coupled to a first
antenna, the operations comprising the steps of: generating a
notification of the receiver being able to receive a reception
frequency band from the first antenna; modifying, in response to
the notification, a radio frequency (RF) transmit path to couple a
given one of at least one filters to or decouple the given filter
from the RF transmit path; and transmitting information in a
selected one of at least one transmission frequency bands and
through the modified RF transmit path to the at least one second
antenna.
35. A mobile station comprising: a first antenna; a second antenna;
a transmitter coupled to the first antenna, the transmitter
comprising first control logic adapted to generate a notification
of a transmission to the first antenna, the transmission using a
selected one of at least one transmission frequency bands; and a
receiver coupled to the second antenna and to the transmitter, the
receiver comprising second control logic and a plurality of
devices, the second control logic adapted to control the plurality
of devices to receive information in a reception frequency band
from the second antenna, the second control logic responsive to the
notification to modify at least one input used by at least a given
one of the devices, the second control logic further adapted to
control the at least one given device and the rest of the plurality
of devices to receive given information, the reception of the given
information occurring for at least some time period while the
transmitter transmits in the at least one transmission frequency
band.
36. The mobile station of claim 35, further comprising a display
device coupled to the receiver and adapted to display at least the
given information.
37. The mobile station of claim 35, wherein: the plurality of
devices comprise a low noise amplifier (LNA); the at least one
input to the LNA comprises biasing current; the second control
logic is responsive to the notification to increase the biasing
current from an initial current to a final current.
38. The mobile station of claim 35, wherein: the plurality of
devices comprise a mixer; the at least one input to the mixer
comprises biasing current; and the second control logic is
responsive to the notification to increase the biasing current from
an initial current to a final current.
39. The mobile station of claim 35, wherein: the plurality of
devices comprise a base band filter; the at least one input to the
base band filter comprises one or more of first values defining a
corner frequency of the base band filter and second values defining
an order of the base band filter; and the second control logic is
responsive to the notification to modify one or more of the first
and second values to reduce bandwidth of the base band filter from
an initial bandwidth to a final bandwidth.
40. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises first and second transmission
frequency bands; the first control logic is adapted to determine a
signal indicating which of first and second transmission frequency
bands is being transmitted; the second control logic is further
responsive to the signal to modify the one or more of the first and
second values when the second transmission frequency band is being
transmitted but not when the first transmission frequency band is
being transmitted.
41. The mobile station of claim 40, wherein: the first transmission
frequency band comprises a 824 to 849 megahertz (MHz) frequency
band; the second transmission frequency band comprises a 1850 to
1910 MHz frequency band; and the reception frequency band comprises
a 1670 to 1675 MHz frequency band.
42. The mobile station of claim 40, wherein: the at least one
transmission frequency band comprises one or more of a 880 to 915
megahertz (MHz) frequency band, a 1710 to 1785 MHz frequency band,
and a 1920 to 1980 MHz frequency band; and the reception frequency
band comprises a 470 to 702 MHz frequency band.
43. The mobile station of claim 35, wherein: the plurality of
devices comprise a signal processing module; the at least one input
to the signal processing module comprises a given input defining
whether or not corrupted sub-carriers of the information should be
removed; and the second control logic is responsive to the
notification to modify the given input to a predetermined state so
that corrupted sub-carriers of the information are removed.
44. The mobile station of claim 43, wherein the signal processing
module is adapted to remove sub-carriers by ignoring the
sub-carrier information.
45. The mobile station of claim 43, wherein the signal processing
module is adapted to remove sub-carriers by ignoring sub-carrier
information from given sub-carriers that are expected to be
corrupted and by using previous information from the given
sub-carriers.
46. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises first and second transmission
frequency bands; the first control logic is adapted to determine a
signal indicating which of the first and second transmission
frequency bands is being transmitted; and the second control logic
is further responsive to the signal to modify the given input to
the predetermined state when the first transmission frequency band
is being transmitted but not when the second transmission frequency
band is being transmitted.
47. The mobile station of claim 46, wherein: the first transmission
frequency band comprises a 824 to 849 megahertz (MHz) frequency
band; the second transmission frequency band comprises a 1850 to
1910 MHz frequency band; and the reception frequency band comprises
a 1670 to 1675 MHz frequency band.
48. The mobile station of claim 46, wherein: the at least one
transmission frequency band comprises one or more of a 880 to 915
megahertz (MHz) frequency band, a 1710 to 1785 MHz frequency band,
and a 1920 to 1980 MHz frequency band; and the reception frequency
band comprises a 470 to 702 MHz frequency band.
49. The mobile station of claim 35, wherein: the plurality of
devices comprise an automatic gain control (AGC) module; the at
least one input to the AGC module comprises a given input, the AGC
module responsive to a predetermined state of the given input to
determine and use a value defining actual amplification of a
variable amplifier in the AGC module; and the second control logic
is responsive to the notification to modify the given input to a
predetermined state so that the ACG module determines and uses the
value.
50. The mobile station of claim 35, wherein: the plurality of
devices comprise an automatic gain control (AGC) module; the at
least one input to the AGC module comprises a plurality of values
defining a signal strength measurement bandwidth of the AGC module;
and the second control logic is responsive to the notification to
modify the plurality of values to decrease bandwidth of the AGC
from an initial bandwidth to a final bandwidth.
51. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises one or more of a 824 to 849
megahertz (MHz) frequency band and a 1850 to 1910 MHz frequency
band; and the reception frequency band comprises a 1670 to 1675 MHz
frequency band.
52. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises one or more of a 880 to 915
megahertz (MHz) frequency band, a 1710 to 1785 MHz frequency band,
and a 1920 to 1980 MHz frequency band; and the reception frequency
band comprises a 470 to 702 MHz frequency band.
53. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises one or more of a 824 to 849
megahertz (MHz) frequency band and a 1850 to 1910 MHz frequency
band; and the reception frequency band comprises a 470 to 702 MHz
frequency band.
54. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises at least one frequency band
defined by a global system for mobile communications (GSM)
standard; and the reception frequency band comprises a frequency
band defined by a digital video broadcasting handheld (DVB-H)
standard.
55. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a code division multiple access (CDMA)
standard; and the reception frequency band comprises a reception
frequency band defined by a digital video broadcasting handheld
(DVB-H) standard.
56. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a wideband code division multiple access
(WCDMA) standard; and the reception frequency band comprises a
reception frequency band defined by a digital video broadcasting
handheld (DVB-H) standard.
57. The mobile station of claim 35, wherein: the at least one
transmission frequency band comprises at least one transmission
frequency band defined by a CDMAOne or CDMA2000 standard; and the
reception frequency band comprises a reception frequency band
defined by a digital video broadcasting handheld (DVB-H)
standard.
58. In a mobile station comprising a first antenna and a second
antenna, a method for operating a transmitter coupled to the first
antenna in combination with a receiver coupled to the second
antenna, comprising: generating a notification of a transmission to
the first antenna, the transmission using a selected one of at
least one transmission frequency bands; and modifying, in response
to the notification, at least one input used by at least a given
one of a plurality of devices in the receiver; and receiving, using
the at least one given device and the rest of the plurality of
devices, information in a second frequency band from the second
antenna, the reception occurring for at least some time period
while the transmitter transmits in the at least one transmission
frequency band.
59. A signal bearing medium comprising a program of
machine-readable instructions executable by an apparatus to perform
operations for operating a transmitter coupled to a first antenna
in combination with a receiver coupled to a second antenna, the
operations comprising the steps of: generating a notification of a
transmission to the first antenna, the transmission using a
selected one of at least one transmission frequency bands; and
modifying, in response to the notification, at least one input used
by at least a given one of a plurality of devices in the receiver;
and receiving, using the at least one given device and the rest of
the plurality of devices, information in a second frequency band
from the second antenna, the reception occurring for at least some
time period while the transmitter transmits in the at least one
transmission frequency band
Description
TECHNICAL FIELD
[0001] This invention relates generally to mobile communications
and, more specifically, relates to receiving and transmitting in a
mobile station.
BACKGROUND OF THE INVENTION
[0002] Terrestrial digital video broadcasting (DVB-T) was first
adopted as a standard in 1997, and has been deployed throughout
many areas of the world. DVB-T offers about 24 megabits per second
(Mb/s) data transfer capability to a fixed receiver, and about 12
Mb/s to receivers in mobile stations. Mobile stations including
such mobile receivers have been made and are able to receive the
DVB-T signals.
[0003] While DVB-T allows high quality video broadcasting to be
delivered to various devices, the DVB-T standard has certain
problems with respect to mobile stations. One such problem is power
usage, as mobile stations that implement DVB-T tend to consume too
much power. Since mobile stations are battery powered unless
plugged into a secondary power source, power usage is a critical
design element. In response to this power usage and other effects
of DVB-T, the DVB-H (a version of DVB for handheld devices)
standard was created. DVB-H offers, among other things, reduced
power usage as compared to DVB-T.
[0004] Because of the benefits of DVB-H over DVB-T, DVB-H is
beginning to make inroads into the mobile station market. For
example, Crown Castle and Nokia are piloting DVB-H technology in
the United States in order to bring television (TV)-like services
to mobile devices. The pilot has started in October, 2004 in the
Pittsburgh, Pa. area, and the pilot aims to prove and test the
feasibility of DVB-H technology and related service systems in the
United States.
[0005] While DVB-H is an improvement over DVB-T, DVB-H also causes
certain problems. For instance, a mobile station typically will
contain at least one transmitter that transmits using one or more
frequency bands. The DVB-H receiver also receives in a frequency
band that is different than the one or more frequency bands used by
any transmitter in the mobile station. For instance, certain mobile
stations can support the global system for mobile communications
(GSM) standard, and the frequency bands used by a GSM transmitter
are different that the frequency band used by a DVB-H receiver.
Nonetheless, transmitting using one frequency band can still cause
interference in the frequency band used by the DVB-H receiver.
[0006] It would therefore be desirable to provide techniques that
can reduce this interference and therefore improve interoperability
between transmitters and receivers in a mobile station.
BRIEF SUMMARY OF THE INVENTION
[0007] The foregoing and other problems are improved upon, and
other advantages are realized, in accordance with exemplary
embodiments of these teachings. In particular, the present
invention provides techniques that improve interoperability between
transmitters and receivers in a mobile station.
[0008] In an exemplary aspect of the invention, exemplary
embodiments are disclosed that perform filtering in a transmitter
to improve interoperability. For instance, in one exemplary
embodiment, a mobile station is disclosed that comprises a first
antenna and at least one second antenna. The mobile station
additionally comprises a receiver coupled to the first antenna. The
receiver comprises first control logic adapted to generate a
notification of the receiver being able to receive a reception
frequency band. The mobile station also comprises a transmitter
coupled to the at least one second antenna and the receiver. The
transmitter communicates radio frequency (RF) signals in a selected
one of at least one transmission frequency bands over an RF
transmit path to the at least one second antenna. The transmitter
comprises second control logic, at least one filter, and at least
one switch. The at least one switch is coupled to the RF transmit
path, the at least one filter, and the control logic. The at least
one switch is adapted to modify the RF transmit path to couple a
given one of the at least one filters to or decouple the given
filter from the RF transmit path. The second control logic is
responsive to the notification to cause the at least one switch to
modify the RF transmit path to couple the given filter to the RF
transmit path.
[0009] In another exemplary embodiment, a method is disclosed for
operating a transmitter coupled to at least one second antenna in
combination with a receiver coupled to a first antenna. The method
comprises the following steps. A notification is generated of the
receiver being able to receive a reception frequency band from the
first antenna. In response to the notification, a radio frequency
(RF) transmit path is modified to couple a given one of at least
one filters to or decouple the given filter from the RF transmit
path. Information is transmitted in a selected one of at least one
transmission frequency bands and through the modified RF transmit
path to the at least one second antenna.
[0010] In another exemplary embodiment, a signal bearing medium is
disclosed that comprises a program of machine-readable instructions
executable by an apparatus to perform operations. The operations
are for operating a transmitter coupled to at least one second
antenna in combination with a receiver coupled to a first antenna.
The operations comprise the following steps. A notification is
generated of the receiver being able to receive a reception
frequency band from the first antenna. In response to the
notification, a radio frequency (RF) transmit path is modified to
couple a given one of at least one filters to or decouple the given
filter from the RF transmit path. Information is transmitted in a
selected one of at least one transmission frequency bands and
through the modified RF transmit path to the at least one second
antenna.
[0011] In another aspect of the invention, exemplary embodiments
are disclosed that change one or more inputs for one or more
devices in a receiver to improve interoperability. For instance, in
an exemplary embodiment, a mobile station is disclosed. The mobile
station comprises a first antenna and a second antenna. The mobile
station additionally comprises a transmitter coupled to the first
antenna. The transmitter comprises first control logic adapted to
generate a notification of a transmission to the first antenna. The
transmission uses a selected one of at least one transmission
frequency bands. The mobile station also comprises a receiver
coupled to the second antenna and to the transmitter. The receiver
comprises second control logic and a plurality of devices. The
second control logic is adapted to control the plurality of devices
to receive information in a reception frequency band from the
second antenna. The second control logic is responsive to the
notification to modify at least one input used by at least a given
one of the devices. The second control logic is further adapted to
control the at least one given device and the rest of the plurality
of devices to receive given information. The reception of the given
information occurs for at least some time period while the
transmitter transmits in the at least one transmission frequency
band.
[0012] In another exemplary embodiment, a method is disclosed for
operating a transmitter coupled to a first antenna in combination
with a receiver coupled to a second antenna. The method comprises
the following steps. A notification is generated of a transmission
to the first antenna. The transmission uses a selected one of at
least one transmission frequency bands. In response to the
notification, a modification is performed of at least one input
used by at least a given one of a plurality of devices in the
receiver. Using the at least one given device and the rest of the
plurality of devices, information is received in a second frequency
band from the second antenna. The reception occurs for at least
some time period while the transmitter transmits in the at least
one transmission frequency band.
[0013] In another exemplary embodiment, a signal bearing medium is
disclosed that comprises a program of machine-readable instructions
executable by an apparatus to perform operations. The operations
are for a transmitter coupled to a first antenna in combination
with a receiver coupled to a second antenna. The operations
comprise the following steps. A notification is generated of a
transmission to the first antenna. The transmission uses a selected
one of at least one transmission frequency bands. In response to
the notification, a modification is performed of at least one input
used by at least a given one of a plurality of devices in the
receiver. Using the at least one given device and the rest of the
plurality of devices, information is received in a second frequency
band from the second antenna. The reception occurs for at least
some time period while the transmitter transmits in the at least
one transmission frequency band.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing and other aspects of embodiments of this
invention are made more evident in the following Detailed
Description of Exemplary Embodiments, when read in conjunction with
the attached Drawing Figures, wherein:
[0015] FIG. 1 is a block diagram of a GSM transceiver;
[0016] FIG. 2 is a block diagram of a mobile station in accordance
with an exemplary embodiment of the present invention;
[0017] FIGS. 3-6A are block diagrams of exemplary portions,
including RF transmit paths, of the mobile station of FIG. 2 and
are used to illustrate filtering of GSM transmission signals;
[0018] FIG. 7 is a block diagram of a mobile station in accordance
with an exemplary embodiment of the present invention and is used
to illustrate filtering of GSM transmission signals;
[0019] FIG. 8 is a block diagram of a transceiver for a dual-mode
mobile station that supports GSM and code-division multiple-access
(CDMA);
[0020] FIG. 9 is a block diagram of a transceiver for a dual-mode
mobile station that supports GSM and CDMA, in accordance with an
exemplary embodiment of the present invention;
[0021] FIG. 10 is a block diagram of a mobile station that improves
operability between a GSM transceiver and a DVB-H receiver; and
[0022] FIG. 11 is a flow chart for improving interoperability
between GSM transceivers and DVB-H receivers.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0023] As previously described, the combination of a transmitter
and a receiver in a mobile station can be problematic. A further
introduction to these problems will now be given. In the examples
below, the mobile station will be considered to have a GSM
transmitter and a DVB-H receiver in the same mobile station,
although the present invention is not limited to this
configuration. A mobile station is any portable device having
wireless capability, such as a cellular phone, a personal digital
assistant (PDA) with cellular or bluetooth capability, and the
like. The mobile station will typically be battery powered.
[0024] In terms of what an operator of the mobile station could
experience while watching digital video using the mobile station,
there are several factors to consider. The business case of the
DVB-H operator is based on good quality video performance, and
cellular connection is not allowed to effect video quality.
Nonetheless, the mobile station performs cellular operations when
delivering back channel information to the interactive DVB-H media
and when the mobile station needs to connect to the base station.
The mobile station needs to connect to the base station
periodically.
[0025] When the mobile station transmits at a cellular frequency,
DVB-H reception quality is decreased. This decrease can be seen as
video flow being not constant or there being blurs in the picture.
A DVB-H frequency band has a number of sub-carriers. The cellular
transmission may destroy all sub-carriers at the same time or may
destroy certain ones of the sub-carriers. For instance, GSM
transmissions occur 4.6 milliseconds (ms) apart with 577
microseconds (.mu.s) transmission time period. The DVB-H time
duration of the useful part of a symbol without guard interval is
for example for 5 MHz channel bandwidth, in 2k mode 358.4 .mu.s,
for 4k mode 716.8 .mu.s, and 8k mode 1433.6 .mu.s.
[0026] The recovery time from the cellular connection disturbance
is not known, but this may be quite long. The recovery time is at
least partially dependent on the algorithm for the automatic gain
control (AGC) of the DVB-H receiver and the performance of the AGC
with strong signals and humping wideband noise.
[0027] The interoperability problem between DVB-H in United States
and the cellular frequency bands will be one of the biggest issues
after service using DVB-H is launched. Both cellular bands for
reception of GSM will generate problems to DVB-H band which is
located between those in frequency domain. The following table
illustrates exemplary transmission and reception bands for GSM and
DVB-H, where "MHz" is megahertz, "U.S." is United States, and
"E.U." is European Union. TABLE-US-00001 Lower GSM Transmission
824-849 MHz Frequency Band in Reception 869-894 MHz U.S. (GSM850)
Lower GSM Transmission 880-915 MHz Frequency Band in Reception
935-960 MHz EU (GSM900) Higher GSM Transmission 1850-1910 MHz
Frequency Band in Reception 1930-1990 MHz U.S. (GSM1900) Higher GSM
Transmission 1710-1785 MHz Frequency Band in Reception 1805-1880
MHz EU (GSM1800) Frequency band in EU Transmission 1920-1980 MHz
(WCDMA2100) Reception 2110-2170 MHz DVB-H Band in U.S. Reception
1670-1675 MHz DVB-H Band in E.U. Reception 470-702 MHz
[0028] The higher US GSM frequency band will generate wideband
noise, which is higher than the minimum DVB-H signal level. The
higher GSM frequency band (GSM1900, typically called the "1900
frequency band" herein) noise at the DVB-H frequency band is -121
dBm/Hz. The required noise level at the minimum DVB-H signal level
is less than -169 dBm/Hz. The difference between actual and
required levels is 48 dB. The assumption is that noise level is
flat and the same level as the GSM reception band noise level.
[0029] In the European Union DVB-H version, the reception band is
on the lower side of the GSM frequency band (GSM900, which is a
transmission frequency band of 880-915 MHz) and the reception
frequency band is far enough that 900 frequency band transmission
is not band-blocking the DVB-H receiver. Nonetheless, the wide band
noise may be a problem also in European DVB-H reception.
[0030] In terms of the U.S. standards, the 850 frequency band
transmission will generate a second harmonic, which will be at the
U.S. DVB-H reception frequency band of 1670-1675 MHz. Also, the 850
frequency band transmission will generate wide band noise to the
U.S. DVB-H frequency band. The most difficult frequencies are
835.0-837.5 MHz in transmission, since these frequencies generate
harmonics directly on top of the U.S. DVB-H frequency band.
[0031] The spurious frequencies near the DVB-H reception channel
will be problematic since the channel filter is not filtering
nearby spurious signals effectively from the DVB-H reception
signal, because the receiver channel selection is designed so that
next channel will be, depending on geographical area, either 5, 6,
7, or 8 MHz apart from the desired received signal. If there are
interference signals nearer than channel raster 5, 6, 7, or 8 MHz
then those interference signals may cause problems since the
channel filter does not filter those completely. A 2.5 MHz band
will include 12.5 GSM RF channels, which will create co-channel
interference.
[0032] The same problem will occur with other U.S. cellular systems
like code-division multiple access (CDMA) and time-division
multiple access (TDMA). This is due to fact that spurious signal
level requirement is 13 dBm by the Federal Communications
Commission (FCC) and in GSM standard the spurious requirement is
-36 dBm. In CDMA, transmission is always on, thus DVB-H reception
is constantly distorted when CDMA is operating with mentioned
difficult RF frequencies or near by frequencies.
[0033] In current DVB-H accessories (such as a video streaming
device by Nokia called SU-22), this receiver desensitizing effect
can be noticed when GSM transmission is on.
[0034] Possible solutions to these problems are as follows. One
possible solution is increased filtering at the 850 and 1900
frequency band transmission signal paths. This is not a good
solution in coming GSM transmitter architectures, since there will
be only one low frequency band (e.g., the 850 and 900 frequency
bands will be combined together) and one high frequency band (e.g.,
the 1800 and 1900 frequency bands will be combined together) will
be used. Therefore, if for instance more filtering is added for the
1900 frequency band signals (which are used for transmission), then
the 1800 frequency band signals are also filtered (which are used
for reception).
[0035] For instance, FIG. 1 shows an exemplary GSM transceiver 100
of a mobile station. The GSM transceiver 100 is used for both
transmission and reception of GSM signals. The GSM transceiver 100
comprises an RF application-specific integrated circuit (ASIC) 110,
a base-band (BB) ASIC 120, and a front-end module (FEM) 150. The BB
ASIC 120 and RF ASIC 110 communicate through in-phase and
quadrature (IQ) signals 115 and RF controls 116. The RF ASIC 110
transmits two frequency bands, the 900 frequency band (e.g., in the
850/900 TX 125) and the 1900 frequency band (e.g., in the 1800/1900
TX 130) to the FEM. The FEM comprises one or more power amplifiers
(PAs) 151, one or more filters 152 (e.g., harmonic filters), FEM
switches 153, and an antenna output 154, coupled to antenna 165.
The filters 152 can perform reception pre-filtering, and the FEM
150 communicates four reception frequency bands, the 850 RX 135,
900 RX 140, 1800 RX 145, and 1900 RX 147, to the RF ASIC 110. The
FEM 150 and the RF ASIC 110 also communicate through RF controls
117, which include reception/transmission (RX/TX) control 118 and
PA biasing 119. The RX/TX control 118 is a signal that indicates
whether the FEM 150 is in a transmit (TX) or a reception (RX) mode.
The PA biasing 119 is a signal that changes PA biasing of the one
or more PAs 151.
[0036] As FIG. 1 shows, if more filtering is added for signals on
the 1900 frequency band, then signals on the 1800 frequency band
are also filtered. Similarly, if filtering is added for signals on
the 900 frequency band, then signals on the 850 frequency band will
also be filtered.
[0037] Yet another problem is as follows. The GSM 1800 transmission
frequency band is from 1710 to 1785 MHz. The U.S. DVB-H reception
frequency band is therefore about 40 MHz lower than the lowest
GSM1800 transmission frequency band. The required filtering is
about 50 dB, which means also noticeable loss at the GSM 1800
lowest channel powers. The current trend is increase radiated
terminal output powers and thus extra loss after the PA 151 is not
beneficial if the loss occurs all the time. For instance, a
frequency filter (e.g., at 1800/1900 MHz) with pass band to stop
band roll-off like 35-40 MHz has easily a remarkable insertion
loss, that degrades both transceiver transmit path and receiver
path.
[0038] If the filtering is done prior to the PA 151, this does not
solve the wide band noise problem because the PA 151 is significant
source of noise. For instance, at the 850 frequency band, harmonics
filtering prior to the PA 151 will not help the situation, since PA
151 is the main contributor to the harmonics.
[0039] Exemplary embodiments of the present invention improve
interoperability between receivers and transmitter in a mobile
station. In an aspect of the invention, filtering is used to filter
certain frequencies of the transmission frequency band. In an
exemplary embodiment, the filtering is performed only when the
DVB-H receiver is able to receive, and this limits power loss due
to filtering. In another aspect of the invention, in response to
the transmitter transmitting (e.g., which can include preparations
for transmitting), the DVB-H receiver modifies one or more inputs
used by a device in the DVB-H receiver. The modification is
performed to improve reception of DVB-H information while the
transmitter is transmitting.
[0040] Referring now to FIG. 2, this figure shows a mobile station
200 in accordance with an exemplary embodiment of the present
invention. The mobile station 200 comprises a GSM transceiver 201,
a DVB-H receiver 202, a display device 204, and an antenna 205. The
DVB-H receiver 208 comprises control logic 208 that controls
operations of the DVB-H receiver 208, such as generating the DVB-H
receiver status signal 203. The display device 204 displays at
least information from the DVB-H receiver 202. The DVB-H receiver
202 is coupled to the RF ASIC 210 using DVB-H receiver status
signal 203. The DVB-H receiver 202 receives a DVB-H RF signal 206
and converts this signal to information (not shown) suitable for
display on the display device 204.
[0041] The exemplary GSM transceiver 201 is used for both
transmission and reception of GSM RF signals 207 using antenna 265,
but could be a transmitter only, if desired. The GSM transceiver
201 comprises an RF ASIC 210, a BB ASIC 220, a FEM 250, and a
selectable RF notch filter 280, and the antenna 265. The antenna
265 need not be part of the GSM transceiver 201. The BB ASIC 220
and RF ASIC 210 communicate through in-phase and quadrature (IQ)
signals (generally: I- and Q-signals comprise information that is
to be transmitted or received) 215 and RF controls 216. The RF ASIC
210 is an RF device that creates and communicates RF signals using
two frequency bands, the 850/900 TX 225 and the 1800/1900 TX 230 to
the FEM. Note that the RF ASIC 210 may comprise multiple RF devices
that create and communicate the RF signals. The FEM comprises one
or more PAs 251, one or more filters 252, FEM switches 253, and an
antenna output 254, coupled to antenna 265. The filters 252 can
perform reception pre-filtering, and the FEM 250 communicates four
reception frequency bands, the 850 RX 235, 900 RX 240, 1800 RX 245,
and 1900 RX 247, to the RF ASIC 210. Typically signals 225, 230,
235, 240, 245, and 247 are individual signal lines. It should be
noted that the frequency bands 225, 230, 235, 240, 245, and 247 are
can be communicated using a bus 291. Typically, only one of the
frequency bands 225-247 occupies the bus 291 at one time and the
bus is made to hold only signals from a currently selected one of
the frequency bands 225-247.
[0042] The FEM 250 and the RF ASIC 210 also communicate through RF
controls 217, which include reception/transmission (RX/TX) control
218 and PA biasing signal 219. The RX/TX control 218 is a signal
that indicates whether the FEM 250 is to be in a transmit (TX) or a
reception (RX) mode. The PA biasing signal 219 is a signal that
changes PA biasing of the one or more PAs 251. The RF ASIC 210
transmits either the 850/900 TX 225 or the 1800/1900 TX 230
frequency bands to the antenna 265 using the RF transmit path 270.
The RF transmit path 270 is any path through which RF signals may
be routed for transmission. For instance, when the GSM transceiver
201 is transmitting using the 850/900 TX 225 frequency band, the RF
transmit path 270 comprises the bus 291, the FEM 250, and the
antenna coupling 261, and, optionally, the antenna 265. The RF ASIC
210 communicates to the selectable RF notch filter 280 using the RF
controls 290, which include the RX/TX control 291 and RF band
information 292. The RX/TX control 291 is a signal that indicates
whether the FEM 250 is to be in a transmit (TX) or a reception (RX)
mode, and may be a copy of the RX/TX control 218 if desired.
Illustratively, the RF band information 292 is a signal having
information used to determine which of the 850, 950, 1800, and 1900
frequency bands is being used.
[0043] Filtering of the transmission signals of one of the 850,
950, 1800, and 1900 frequency bands is done adaptively by using
transmission on/off information (e.g., in the RX/TX control 291)
and operating frequency band information (e.g., in the RF band
information 292). In an exemplary embodiment, the filter used in
the selectable RF notch filter 280 is a branch-selectable notch
filter, which has multiple selections with multiple notch rejection
specifications. Exemplary selectable RF notch filters 280 are shown
in FIGS. 3-6A.
[0044] The DVB-H receiver status signal 203 can be used to
determine when filtering is performed. In one exemplary embodiment,
the DVB-H receiver status signal 203 is a signal indicating whether
the DVB-H receiver 202 is in a reception mode. In response to the
DVB-H receiver being in a reception mode, the GSM transceiver 201
performs filtering of transmitted GSM signals. In another exemplary
embodiment, the DVB-H receiver 202 could be contained in a
removable module (not shown). When the removable module is coupled
to the mobile station 200, the DVB-H receiver status signal 203
indicates that the removable module is coupled to the mobile
station 200, and the GSM transceiver 201 performs filtering of
transmitted GSM signals in response to the DVB-H receiver status
signal 203. Note that the DVB-H receiver status signal 203 could be
determined through a query by the RF ASIC 210 to the DVB-H receiver
202.
[0045] When notch filtering is used, then higher losses can be
expected in the signal communicated on the RF transmit path 270 to
the antenna 265. Thus, notch filtering means lower radiated output
power. For this reason, the extra notch filtering, in an exemplary
embodiment, is used only when needed.
[0046] Consequently, a notch is selected based on operating
frequency band and a notch is typically selected only when
transmission is on. The selectable RF notch filter 280 modifies the
RF transmit path 270 to couple one or more filters to or decouple
one or more filters from the RF transmit path 270. Since extra
filtering increases loss to the RF transmit path 270, filtering is
removed when GSM is in reception mode. This way, GSM sensitivity
can be maintained.
[0047] The notch filtering in the 850 frequency band is typically
performed for the second harmonic rejection and may be performed
for wide band noise filtering (e.g., noise that is converted to
1670-1675 MHz frequency band). In 900/1800/1900 frequency bands,
the filtering is done to suppress wide band noise. Noise from 900
MHz for EU DVB-H frequency band, and noise from 1800/1900 MHz to US
DVB-H frequency band are wide band noise at their nature. A "notch
filter" in this context is, e.g., a filter with a bandwidth
sufficient to cover a DVB-H frequency band. This kind of filter can
be referred as notch-filter, and noise can be referred as wideband
noise. It is not an intention (though it is possible) to filter
wideband, just a DVB-H frequency band (e.g., only US or EU) or
frequency bands (e.g., both US and EU).]
[0048] Furthermore, the PA 251 can be linearized by changing the PA
biasing signal 219 to cause the PA 251 to perform closer to or at
class A operation. Typically, this means a value of current on the
PA biasing signal 219 would be increased. Class A operation should
reduce the magnitude of the harmonics. This more linear operation
will consume more power and generate more heat, but this more
linear mode is needed only when the GSM transceiver 201 is
transmitting (e.g., which can include preparations to transmit) at
the same time a DVB-H module is in reception mode. This way total
current consumption is not increased significantly.
[0049] The control logic 285, as part of the RF ASIC 210,
communicates the RF controls 290 to the selectable RF notch filter
280. The control logic 285 also, in one exemplary embodiment,
controls operations of the GSM transceiver 701. It should be noted
that a portion or all of the control logic 285 may reside in
locations other than the RF ASIC 210, such as being distributed
between the RF ASIC 210 and the BB ASIC 220 or being its own module
separate from the RF ASIC 210 or the BB ASIC 220. Additionally, the
control logic 285 can adjust the PA biasing signal 219. Note that a
control logic portion can be added to the selectable RF notch
filter 280, if desired, so that the selectable RF notch filter 280
will determine, using signals from the RF ASIC 210 and the DVB-H
receiver 208, what filter should or should not be coupled to the
antenna coupling 261. The RX/TX logic 286 determines whether the RF
ASIC 210 is in a transmission or reception mode and informs the
control logic 285 of the mode. The RX/TX logic 286 (e.g., and the
control logic 285) would typically be part of control logic 285 for
the RF ASIC 210.
[0050] Although the RF ASIC 210, BB ASIC 220, and FEM 250 are shown
as being separate, portions or all of the three may be combined or
further sub-divided. Additionally, some or all of the functionality
of the three may be performed by processors such as a digital
signal processor (DSP), hardware such as very large scale
integrated circuits (VLSI), or programmable logic devices (e.g.,
using read only memories) such as field programmable gate arrays
(FPLGA), or some combination of these or any other suitable device.
The signals herein may be, for instance, signals that travel on
conductive elements, such as traces or wires, or may be one or more
messages that are passed between software modules.
[0051] Referring now to FIG. 3, a possible portion 399, including
one exemplary RF transmit path portion 370, of the mobile station
200 of FIG. 2 is shown. RF transmit path portion 370 is a portion
of RF transmit path 270. The portion 399 comprises the FEM 250, the
antenna coupling 261, the selectable RF notch filter 300, and
optionally the antenna 265. The selectable RF notch filter 300
comprises a switch 320 and a switch 310. In response to RX/TX
control 291, the switch 320 switches between the RX connection
(e.g., when the GSM transceiver 201 is in a reception mode) and the
TX connection (e.g., when the GSM transceiver 201 is in a
transmission mode). In response to the RF band information 292, the
switch 310 switches between connection 311 (e.g., when the GSM
transceiver 201 is transmitting using the GSM 850 frequency band),
which couples a notch filter 330 to the RF transmit path portion
370, and the connection 312 (e.g., when the GSM transceiver 201 is
transmitting using the GSM 1900 frequency band), which couples a
notch filter 340 to the RF transmit path portion 370. Note that for
the EU DVB-H system: the kind of functionality in FIG. 3 may be
used at GSM 900 and 1800.
[0052] Thus, there are three different options for notch filter
selection based on transmission or reception and operating
frequency band:
[0053] Notch 1 (i.e., notch filter 330) option: Used when the GSM
850 frequency band is being used for transmission, and the
filtering is performed for second harmonic and wide band noise
filtering;
[0054] Notch 2 (i.e., notch filter 340) option: Used when the GSM
1900 frequency band is being used for transmission, and the
filtering is performed for wideband noise filtering; and
[0055] Not connected (i.e., the RX connection in switch 320, which
connects to the not connected terminal 321) option: Used when the
GSM transceiver 201 is in a reception mode. The not connected
option does not add extra loss to the RF transmit path portion 370
and thus receiver sensitivity can be maintained.
[0056] The notch filters 330, 340 could be realized, for instance,
with ceramic components or bulk acoustic wave (BAW) components, or
micro-electromechanical switches (MEMS). The notch filters 330, 340
may also be realized using surface-mount devices (SMDs).
[0057] FIG. 4 shows another possible exemplary portion 499,
including the RF transmit path portion 470, of the mobile station
200 of FIG. 2. Transmit path portion 470 is a portion of the RF
transmit path 270 of FIG. 2. The exemplary portion 499 comprises a
gallium arsenide (GaAs) switch 300 having three positions. The GaAs
switch 400 is responsive to the RX/TX control 291 and the RF band
information 292 to select one of the switches. Note that the RX/FX
control 291 and the RF band information 292 may be combined into
two control signals if desired. The GaAs switch 400 has a first
position that couples the notch filter 330 to the antenna coupling
261, a second position that couples the notch filter 340 to the
antenna coupling 261, and a third position that couples a not
connected terminal to the antenna coupling 261.
[0058] FIG. 5 shows another exemplary portion 599, including the RF
transmit path portion 570, of the mobile station 200 of FIG. 2.
Transmit path portion 570 is a portion of the RF transmit path 270
of FIG. 2. In the example of FIG. 5, the selectable RF notch filter
500 comprises two switches 510, 520, which could be GaAs FETs or
PIN-diodes. Each switch 510, 520 has a corresponding control signal
C1 511, C2 521. The control signals C1 511 and C2 521 are
controlled as shown in table 530 of FIG. 5. In this example, when
C1 511 is zero and C2 521 is zero, this is a not connected option.
The Notch 1 option is chosen when C1 511 is one and C2 521 is zero,
while the Notch 2 option is chosen when C1 511 is zero and C2 521
is one. One exemplary technique for generating the control signals
C1 511 and C2 521 is by having the control logic 285 (see FIG. 2)
generate the control signals C1 511 and C2 521 from data about
whether the GSM transceiver 201 is transmitting and, if so, on what
frequency band. The notch filters 330, 340 are selectable
resonances. Note that control logic could be built into the
selectable RF notch filter 500 so that the selectable RF notch
filter generates the control signals C1 511 and C2 521 based on
signals from the RF ASIC 210.
[0059] Turning now to FIG. 6, another exemplary possible portion
699, including RF transmit path portion 670, is shown of the mobile
station of FIG. 2. The portion 699 comprises the FEM 150, two
switches 610, 640, a noise filter 620 for the GSM 1900 frequency
band, a notch filter 630 for the GSM 850 frequency band, a
filtering control signal 645, the antenna coupling 261, and
optionally the antenna 265. FIG. 6 illustrates an alternative
proposal for a filter arrangement and is a filter bank approach.
The switches 610 and 640 are responsive to the filtering control
signal 645 to modify the transmit portion 670 to couple the noise
filter 620 or notch filter 630 to the RF transmit path portion 670
or to uncouple the noise filter 620 and notch filter 630 from the
RF transmit path portion 670 (e.g., using the unfiltered connection
650). When the GSM transceiver 201 is transmitting using the GSM
850 frequency band, the switches 610 and 640 couple the notch
filter 630 to the RF transmit path portion 670. When the GSM
transceiver 201 is transmitting using the GSM 1900 frequency band,
the switches 610 and 640 couple the noise filter 620 to the RF
transmit path portion 670. When the GSM transceiver 201 is
transmitting on the GSM 900 or 1800 frequency bands or is receiving
(e.g., or the DVB-H receiver 202 is not in a reception mode), the
switches 610 and 640 couple the unfiltered connection 650 to the RF
transmit path portion 670.
[0060] FIG. 6A is an alternative implementation for the radio
transmitter presented in FIG. 6. One difference is the second
antenna 660, which is connected to notch filter 630. When a
filtered signal 631 is transmitted directly from filter 630 via
antenna 660, then linearity and harmonic suppression can be
maintained. Also transmitted output power can be increased by
insertion loss of switch 640. Also a similar kind of extra antenna
670 can be connected to noise filter 620 and the same benefits
would occur with the filtered signal 621.
[0061] Turning now to FIG. 7, a mobile station 700 is shown in
accordance with an exemplary embodiment of the present invention.
Mobile station 700 contains many of the components shown in FIG. 2.
In this example, however, the GSM transceiver 701 comprises a
selectable RF notch filter 705 that also uses the RX on/off signal
703. The DVB-H receiver 702 comprises control logic 708 that
generates the RX on/off signal 703. The RX on/off signal 701 is a
signal indicating whether the DVB-H receiver 702 is or is not in a
reception mode. The selectable RF notch filter 705 comprises filter
selection logic 710 that uses the RF controls 291 and the RX on/off
signal 703 to select and couple a filter (see FIGS. 3-6) to the
antenna coupling 261 or to decouple the filter from the antenna
coupling 261. The filter selection logic 710 is control logic for
the selectable RF notch filter 705. The RX on/off signal 703 may be
enabled by the DVB-H receiver 702 when the DVB-H receiver 702 is in
a reception mode, or logic in the selectable RF notch filter 705
can query the DVB-H receiver 702 for the RX on/off signal 703.
[0062] In the filtering scheme of FIG. 7, whether the DVB-H
receiver 702 is in a reception mode or not (e.g., as indicated by
the RX on/off signal 703) is used also for filter selection. The
DVB-H receiver 702 typically receives for a few hundred
milliseconds and then the DVB-H receiver 702 is in idle mode for a
few seconds. When the DVB-H receiver 702 is in an idle mode, extra
filtering is not needed.
[0063] When the RX on/off signal 703 is also used for controlling
filtering of frequency bands, then filtering is generally used only
when the DVB-H receiver 702 is in a reception mode (e.g., actively
receiving or possibly preparing to receive) and a GSM frequency
band is being transmitted by the GSM transceiver 701 at the same
time.
[0064] Alternative techniques for filtering U.S. DVB-H channel
noise caused by GSM transmissions can be performed in dual-mode GSM
and wide-band CDMA (WCDMA) mobile stations. A typical dual-mode
transceiver 800, for use in a dual mode GSM/WDCMA mobile station,
is shown in FIG. 8. Transceiver 800 comprises an RF ASIC 810, a GSM
bus 820, a GSM PA 830, a WCDMA bus 840, a WCDMA PA 850, a duplex
filter 860, antennas 865 and 870, and antenna couplings 831, 841,
and 875. GSM signals are transmitted over the GSM bus 820, and
WCDMA signals are transmitted over the WCDMA bus 840.
[0065] Future U.S. products will include WCDMA operation at both
cellular frequency bands 850 and 1900, and at the both of these
frequency bands GSM operation will also continue. These future U.S.
products, an exemplary transceiver 800 of which is shown in FIG. 8,
will be dual-band products with dual-mode operation.
[0066] Since WCDMA and GSM are operating at the same frequency, one
common antenna (e.g., antenna 865, coupled to the duplex filter 860
using the antenna coupling 875) can be used or separate antennas
(e.g., antenna 865 and antenna coupling 831 for GSM and antenna 870
and antenna coupling 841 for WCDMA) for both systems can be used.
The dotted lines in FIG. 8 indicate optional arrangements.
[0067] FIG. 8 shows only WCDMA duplex filter 860, but in fact for
each frequency band 850 and 1900, one duplex filter 860 is needed.
Additionally, a duplex filter 860 typically contains two pass-band
filters: one for reception and one for transmission.
[0068] Referring now to FIG. 9, this figure shows a dual-mode
transceiver 900 operating in accordance with an exemplary
embodiment of the present invention. Transceiver 900 comprises an
RF ASIC 910, a GSM bus 920, a GSM PA 930, a WCDMA bus 940, a WCDMA
PA 950, two duplex filters 960 and 961, a switch module 950,
antennas 965 and 970, and antenna couplings 931, 941, and 975, and
two switch outputs 921, 922. The RF ASIC 910 is an RF device that
creates and communicates RF signals using one of several frequency
bands. Note that the RF ASIC 910 may comprise multiple RF devices
(e.g., one RF device could create and communicate RF signals
defined by the GSM communication protocol, while another RF device
creates and communicates RF signals defined by the WCDMA protocol).
When a DVB-H receiver (not shown in FIG. 9) is not coupled to the
dual-mode transceiver 900 or is not in a reception mode (e.g.,
receiving), signals defined by the GSM communication protocol are
typically transmitted over the GSM bus 920 and the switch output
921, and signals defined by the WCDMA communication protocol are
transmitted over the WCDMA bus 940 and the switch output 922.
[0069] As with FIG. 8, since the communication protocols of WCDMA
and GSM are operating at the same frequency, one common antenna
(e.g., antenna 965, coupled to the duplex filter 960 using the
antenna coupling 975) can be used or separate antennas (e.g.,
antenna 965 and antenna coupling 931 for GSM and antenna 970 and
antenna coupling 941 for WCDMA) for each communication protocol can
be used. The dotted lines in FIG. 9 indicate optional arrangements
for the antennas 965, 970 and antenna couplings 931, 941, and 975.
FIG. 9 shows that for each frequency band 850 and 1900, one duplex
filter 960 (e.g., the frequency band 850) or 961 (e.g., the
frequency band 1900) is typically used. Additionally, a duplex
filter 960 or 961 typically contains two pass-band filters: one for
reception and one for transmission.
[0070] In FIG. 9, the switch module 950 comprises two switches 951
and 952. The control logic 955 uses an input from the DVB-H
receiver (not shown in FIG. 9) to determine the control signal 956,
which in this example is two bits. The control signal 956 is also
determined using the transmitting frequency bands for GSM. The
control of the GSM routing to WCDMA transmitter is controlled with
operating band information and when DVB-H is active.
[0071] The switch module 950 is responsive to states of the control
signal 956 and will modify the RF transmit path 970 to couple the
duplex filters 960, 961 to the RF transmit path 970 when certain
conditions are met. The RF transmit path 970 is modified so that
the duplex filters 960, 961 are coupled to the RF transmit path 970
by coupling the GSM bus 920 to the switch output 922, so that the
WCDMA PA 950 and the duplex filters 960, 961 (e.g., and possibly
the antenna 970) become part of the RF transmit path 970. In the
example of FIG. 9 and as shown in table 957, the GSM bus 920 is
coupled to the WCDMA PA 950 when the control signal 956 has a state
where two bits are a zero and a one. For other versions of the
control signal 956, the RF transmit path 970 is modified by the
switch module 950 to decouple the duplex filter 960 from the RF
transmit path 970 for GSM signals from the RF ASIC 910. For
instance, the GSM bus 920 remains coupled to the GSM PA 930 when
the control signal 956 has a state where two bits are both zeros.
The WCDMA bus 940 remains coupled to the WCDMA PA 950 when the
control signal 956 has a state where two bits are both ones. The
state of having a first bit being a one and a second bit being a
zero for the control signal 956 is not allowed in this example. It
should be noted in FIG. 9 that there is only one RF transmit path
970, as both WCDMA and GSM signals will not be transmitted at the
same time.
[0072] In WCDMA mode (e.g., both bits of the control signal 956 are
ones in the example of FIG. 9), the transmission is filtered after
the WCDMA PA 950 with a duplex filter 960. Transmission filters
(not shown) in the duplex filters 960, 961 will attenuate
transmission harmonics and wide band noise. For at least this
reason, a GSM transmission can be filtered by the duplex filters
960, 961.
[0073] The duplex filters 960, 961 will increase loss after the
WCDMA PA 950 and thus lower transmitted output power is delivered
to antenna 965 (e.g., or 970). For this reason, it is beneficial
that the GSM transmission is filtered only when DVB-H receiver is
in a reception state. In FIG. 9, "GSM" means both the 850 and 1900
frequency bands for the GSM communication protocol and "WCDMA"
means both the 850 and 1900 frequency bands for the WCDMA
communication protocol. Additionally, in FIG. 9, the GSM PA 930
includes both GSM frequency band 850 and 1900 amplifiers and the
WCDMA PA 950 includes both WCDMA frequency band 850 and frequency
band 1900 amplifiers.
[0074] FIGS. 2-7 and 9 have shown examples of how interoperability
between receivers and transmitters can be improved in a mobile
station. FIGS. 2-7 and 9 use filtering, among other things, to
improve interoperability.
[0075] FIGS. 10 and 11 illustrate other exemplary techniques for
improving interoperability between receivers and transmitters in a
mobile station. In particular, in response to a transmission (e.g.,
which can include preparations to transmit) the DVB-H receiver is
adjusted, preferably by modifying inputs used by devices in the
DVB-H receiver.
[0076] Turning now to FIG. 10, a mobile station 1000 is shown.
Mobile station 1000 comprises a GSM transceiver 1010 coupled to a
DVB-H receiver 1020. DVB-H receiver 1020 comprises control logic
1030, an LNA 1035, a mixer 1040, one or more filters 1045, a signal
processing module 1050, and an AGC module 1055. The AGC module 1055
comprises an AGC algorithm 1061. The signal processing module 1050
comprises one or more digital filters 1070. The control logic 1030
controls operations of the DVB-H receiver 1020, such as controlling
the LNA 1035, mixer 1040, filters 1045, signal processing module
1050, and AGC module 1055 to receive information in the DVB-H
frequency band of the DVB-H RF signal 1090. Certain signals are
coupled between the GSM transceiver 1010 and the DVB-H receiver
1020. The control logic 1011 of the GSM transceiver 1010 generates
these signals. In the example of FIG. 10, the following signals are
coupled between the GSM transceiver 1010 and the DVB-H receiver
1020: 850 or 1900 operation 1005; RX/TX on/off 1006; RX/TX signal
level 1007; and used RF channel 1008. Note that not all of these
signals need to be used and additional signals may be provided, if
desired. The control logic is responsive to the signals 1005-1008
and modifies one or more of the value(s) 1036, 1041, 1051, and 1061
in response to one or more of the signals 1005-1008.
[0077] The channel numbers of different GSM systems are shown in
table below: TABLE-US-00002 GSM system Lowest channel number
Highest channel number GSM850 128 251 GSM900 975 124 GSM1800 512
885 GSM1900 512 810
[0078] From this table, it can be seen that the same channel
numbers are used in different GSM systems. Thus operational band
information is needed for controlling purposes.
[0079] The signal 1007 information can be used for the optimization
purposes. When transmission signal levels are known, then the DVB-H
receiver can be linearized only to a needed level. This is
desirable since a more linear mode consumes more power.
[0080] Additionally, some or all of the functionality (e.g.,
including the devices 1035, 1040, 1045, 1050, and 1055) of the
DVB-H receiver 1010 may be performed by processors such as a
digital signal processor (DSP), hardware such as very large scale
integrated circuits (VLSI), or programmable logic devices (e.g.,
using read only memories) such as field programmable gate arrays
(FPLGA), or some combination of these or any other suitable device.
The signals herein may be, for instance, signals that travel on
conductive elements, such as traces or wires, or may be one or more
messages that are passed between software modules.
[0081] Referring now to FIG. 11, with appropriate reference to FIG.
10, a method 1100 is shown for improving interoperability between
the GSM transceiver 1010 and the DVB-H receiver 1020 in the mobile
station 1000. Method 1100 is typically performed by the control
logic 1030.
[0082] In step 1110, it is determined if the GSM transceiver 1010
is in transmission mode (e.g., or is not in a reception mode).
Adjustment is not needed when the GSM transceiver 1010 is in
reception mode (step 1110=No), and default inputs are applied to
the devices 1035, 1040, 1045, 1050, and 1060 by using inputs 1041,
1046, 1051, and 1061. Note that the GSM transceiver 1010 may also
have an idle mode, and default inputs would also be applied to the
devices when the GSM transceiver 1010 is in idle mode.
[0083] If the GSM transceiver 110 is operating in transmission mode
(step 1110=Yes), then the method continues in step 1130. Note that
one or all of steps 1130 through 1160 may be performed.
[0084] In step 1103, the LNA 1035 and mixer 1040 are adjusted using
inputs 1036 and 1041, respectively. It should be noted that the LNA
1035 and the mixer 1040 may be separately adjusted, if desired. The
inputs for the LNA 1035 and mixer 1040 are modified for more linear
mode with higher noise figure when harmonics are transmitted in
order to avoid compression. This way, the DVB-H receiver 1020 can
better tolerate interference signals.
[0085] Increasing the biasing current (e.g., as input 1036) of the
LNA 1035 can force the LNA 1035 to a more linear mode. The same
applies also for mixer 1040 (e.g., increasing the biasing current
as input 1041 to the mixer 1040 can force the mixer 1040 to a more
linear mode). In normal operation mode (step 1120), the LNA 1035
and mixer 1040 are biased (e.g., using inputs 1036 and 1041) to a
low biasing mode in order to achieve a long operating time for the
mobile station 1000. The high biasing mode (step 1130) is typically
only used when high interference signal of a GSM transmission is
present. This high biasing mode consumes more power and thus
reduces operating time of the mobile station 1000.
[0086] Note that step 1130 will typically change to high biasing
mode when the GSM transceiver 1010 is transmitting on either of the
850 or 1900 frequency bands (e.g., as indicated by the RX/TX On/off
signal 1006).
[0087] In step 1140, DVB-H RF filtering, as performed by filter(s)
1045, is modified based on GSM transmission frequency information.
The GSM transmission frequency information can be determined using
the signal used RF channel 1008, which indicates whether the 850 or
1900 frequency band was used, and the 850 or 1900 operation signal
1005, which indicates whether one of the frequency bands 850 or
1900 is being used to transmit. Step 1140 is typically used when
GSM harmonics will fall near the frequency band used by the DVB-H
RF signal 1090 but the actual harmonic is outside of the frequency
band used by the DVB-H RF signal 1090 (e.g., an out-of-band
blocker). Step 1140 is used, for instance, for the 1900 frequency
band, which generates harmonics outside of the frequency band used
by the DVB-H RF signal 1090.
[0088] The filtering can be changed at the base band filtering
(performed, e.g., by filters 1045) and in filtering performed by
the signal processing module 1050. Typically, the signal processing
module 1050 is implemented at least partially by a DSP. The base
band filtering can be modified by reducing the signal bandwidth.
The actual modification is the modification of a corner frequency
of a low pass filter 1045 or modification of an order of the filter
1045 or both. These modifications may be performed through inputs
1046, which are typically values associated with the filter 1045.
The modification of order may improve performance of the DVB-H
receiver 1020 when the signal interference caused by the GSM
transmission is near the DVB-H frequency band. Analog domain
filtering is done to protect an analog-to-digital converter (not
shown) in the DVB-H receiver 1020 from not saturating due to strong
interference signals.
[0089] The filtering (e.g., digital filter 1070) performed by the
signal processing module 1050 can be changed by altering the
filtering coefficient (e.g., an input 1051) of a finite impulse
response (FIR) filter implemented by the signal processing module
1050. Filtering performed by the signal processing module 1050 may
also be used to filter sub-carriers of the DVB-H RF signal 1090
(see step 1150 below). The filtering performed by the signal
processing module 1050 also corrects non-idealities caused by
analog filtering. The non-idealities comprise amplitude and phase
corrections.
[0090] In step 1150, corrupted sub-carriers are removed. The DVB-H
signal is an orthogonal frequency division multiplexed (OFDM)
signal which includes a number of sub-carriers (in 2k mode 1705, 4k
mode 3409 and 8k mode 6817 sub-carriers). When GSM channel number
(e.g., through used RF channel signal 1008) is submitted to the
DVB-H receiver 1020, the signal processing module 1050 (e.g.,
implemented using a DSP) can remove corrupted sub-carriers, because
GSM harmonics will completely destroy only selected sub-carriers.
Step 1150 is typically performed when transmission in a GSM
frequency band, such as the 850 frequency band, generates harmonics
inside of the frequency band used by the DVB-H RF signal 1090
(e.g., co-channel interference or spurious interference).
[0091] The corrupted sub-carriers can be removed by ignoring the
sub-carrier information. This is the easiest technique to implement
removal of sub-carriers. An alternative technique is to ignore
sub-carrier information from sub-carriers that are expected to be
corrupted and to use previous information (e.g., stored
information) from these sub-carriers. This stored information is
added to new information from other carriers and this mixed
combined signal is filtered and further processed.
[0092] In step 1150, the control logic 1030 modifies an input 1151
to the signal processing module 1050, and the signal processing
module 1050 is responsive to the modified input 1151 to filter
corrupted sub-carriers. For instance, the input 1151 could be a
default message (e.g., "perform normal processing") when the used
RF channel signal 1008 indicates that the 850 frequency band is not
being used for transmission, and the input 1151 could be a
different message (e.g., "remove sub-carriers") when the used RF
channel signal 1008 indicates that the 850 frequency band is being
used for transmission.
[0093] The impact of the sub-carrier removal is that raw bit-error
rate will increase but if the bit-per-symbol interleaving is done
over several sub-carriers and over multiple symbol times, then this
sub-carrier information removal may be corrected. The correction is
based on signal interleaving and information coding. The actual
performance reduction, which can be seen by sub-carrier removal, is
a function of the performance of interleaving and coding and the
signal bandwidth of DVB-H RF signal 1090.
[0094] In step 1160, the AGC module 1055 can be altered, using
inputs 1061 and typically the AGC algorithm 1060, when harmonics
are present, such as when the 850 frequency band is being used to
transmit. In this manner, the recovery time from the high power
spurious signals can be improved. For instance, an AGC value which
determines actual amplification of the variable gain amplifier (not
shown) before spurious signals are present (e.g., as determined by
the 850 or 1900 operation signal 1005 and the used RF channel
signal 1008) can be used until after the spurious signals
disappear. For instance, the control logic 1030 could cause an
input 1061 to be modified that in turn causes the AGC algorithm
1060 to "freeze" its value until the input 1061 is again modified.
Another possibility is that AGC bandwidth can be altered (e.g.,
such as by modifying values using inputs 1061 of a filter used by
the AGC 1055) when narrow-bandwidth spurious signals are expected
to appear.
[0095] Exemplary embodiments of the present invention have been
described thus far in terms of specific examples of frequency bands
and the like. However, it should be kept in mind that these
teachings can be applied to other frequency bands, such as the
frequency bands of 470-702 MHz that are allocated in the E.U. for
DVB-H broadcasts, and to other the cellular transmission bands such
as those produced by TDMA and/or CDMA cellular systems.
[0096] Also, while the above disclosure of the presently preferred
embodiments has concentrated on the use of the DVB-H and GSM
systems, those skilled in the art should realize that these should
not be read as limitations on the practice of this invention, and
that other types of communications systems using the same or
different frequency bands may also benefit from the use of this
invention.
[0097] It should be noted that embodiments of the present invention
might be implemented on a signal bearing medium comprising a
program of machine-readable instructions. The machine-readable
instructions are executable by an apparatus to perform operations
of one or more steps involved with the present invention.
[0098] Furthermore, filtering of a GSM signal is shown occurring at
the antenna coupling 261, but other locations are possible. For
instance, filtering could occur before the PA 251 of FIGS. 2 and 7,
although filtering before the PA 251 may be less beneficial than
filtering after the PA 251.
[0099] Additionally, the techniques presented above may be used for
other frequency bands, such as the frequency bands specified by the
CDMAOne and CDMA2000 standards. Broadly, any frequency band that
can cause problems with DVB_H frequency bands may be filtered
(e.g., FIGS. 2-10), inputs of devices in a DVB-H receiver modified
(e.g., FIGS. 10 and 11), or both.
[0100] The foregoing description has provided by way of exemplary
and non-limiting examples a full and informative description of the
best method and apparatus presently contemplated by the inventors
for carrying out the invention. However, various modifications and
adaptations may become apparent to those skilled in the relevant
arts in view of the foregoing description, when read in conjunction
with the accompanying drawings and the appended claims. However,
all such and similar modifications of the teachings of this
invention will still fall within the scope of this invention.
[0101] Furthermore, some of the features of the preferred
embodiments of this invention could be used to advantage without
the corresponding use of other features. As such, the foregoing
description should be considered as merely illustrative of the
principles of the present invention, and not in limitation
thereof.
* * * * *