Indian Patents. 257698:A TRANSMITTER AND A RECEIVER IN A COMMUNICATION SYSTEM FOR INCREASED PERFORMANCE IN SPACE-TIME FREQUENCY BLOCK CODING AND METHODS THEREFORE

Title of Invention	A TRANSMITTER AND A RECEIVER IN A COMMUNICATION SYSTEM FOR INCREASED PERFORMANCE IN SPACE-TIME FREQUENCY BLOCK CODING AND METHODS THEREFORE
Abstract	The invention relates to a space-time-frequency block coding apparatus and method in a transmitter with three transmit (Tx) antennas are provided. An input symbol sequence is transmitted through three Tx antennas according to a set method using feedback information received from a receiver or using a selected transmission matrix having regularities in order to improve the performance of an STFBC.

Full Text	WE CLAIM : 1. A transmitter with three transmit antennas in a communication system using a space-time-frequency block coding scheme, comprising: a pre-coder for pre-coding a symbol vector of an input symbol sequence; and a space-time frequency block code (STFBC) mapper for selecting an SFTBC based on feedback channel quality indicators (CQIs) received from a receiver, mapping the pre-coded symbols to the transmit antennas according to the selected STFBC, and transmitting the mapped symbols through the transmit antennas; wherein the STFBC mapper selects the STFBC based on the feedback CQIS according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 2. The transmitter as claimed in claim 1, wherein the pre-coder pre- codes the symbol vector of an input symbol sequence by multiplying the symbol vector by ejθ' θ being a phase rotation angle. 3. The transmitter as claimed in claim 1, wherein the STFBC mapper comprises a mapper for mapping the pre-coded symbols to the transmit antennas according to the selected STFBC and transmitting the mapped symbols through the transmit antennas. 4. The transmitter as claimed in claim 1, wherein the selected STFBC is transmitted to the receiver. 5. The transmitter as claimed in claim 3, wherein the selected STFBC is transmitted to the receiver. 6. The transmitter as claimed in claim 1, wherein each of the feedback CQIs is the average channel information of a plurality of subcarriers. 7. The transmitter as claimed in claim 3, wherein each of the feedback CQIs is the average channel information of a plurality of subcarriers. 8. A transmitter with three transmit antennas in a communication system using a space-time-frequency block coding scheme, comprising: a pre-coder for pre-coding a symbol vector of an input symbol sequence; and a space-time-frequency block code (STFBC) mapper for selecting an STFBC based on feedback channel quality indicators (CQIS) received from a receiver, mapping the pre-coded symbols to the transmit antennas according to the selected STFBC, and transmitting the mapped symbols through the transmit antennas; wherein the STFBC mapper selects the STFBC based on the feedback CQIs according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 9. The transmitter as claimed in claim 8, wherein the pre-coder pre- codes the symbol vector of an input symbol sequence by multiplying the symbol vector by ejθ, θ being a phase rotation angle. 10. The transmitter as claimed in claim 8, wherein the STFBC mapper comprises a mapper for mapping the pre-coded symbols to the transmit antennas according to the selected STFBC, and transmitting the mapped symbols through the transmit antennas. 11. The transmitter as claimed in claim 8, wherein the selected STFBC is transmitted to the receiver. 12. The transmitter as claimed in claim 10, wherein the selected STFBC is transmitted to the receiver. 13. A receiver in a communication system having a transmitter with three transmit antennas and using a space-time-frequency block coding scheme, comprising: a channel estimator for channel-estimating a signal received through a receive antenna and outputting channel quality indicators (CQIs); and a feedback transmitter for transmitting the CQIs to a space-time- frequency block code (STFBC) mapper of a transmitter; wherein the CQIs are used in the transmitter to select an STFBC according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 14. The receiver as claimed in claim 13, wherein each of the CQIS is the average channel information of a plurality of subcarriers. 15. A receiver in a communication system having a transmitter with three transmit antennas and using a space time frequency block coding scheme, comprising: a channel estimator for channel-estimating a signal received through a receive antenna and outputting channel quality indicators (CQIs); and a feedback transmitter for transmitting a space-time-frequency block code (STFBC) index obtained using the CQIS to an STFBC mapper of a transmitter; wherein the STFBC index is obtained at the receiver according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 16. A space-time-frequency block coding method in a transmitter with three transmit antennas, comprising the steps of: pre-coding a symbol vector of an input symbol sequence; and selecting a space-time-frequency block code (STFBC) based on feedback channel quality indicators (CQIs) received from a receiver, for mapping of the pre-coded symbols; wherein the STFBC selecting step comprises the step of selecting the STFBC based on the feedback CQIs according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 17. The space-time-frequency block coding method as claimed in claim 16, wherein the pre-coding the symbol vector of the input symbol sequence comprises, pre-coding the symbol vector of an input symbol sequence by multiplying the symbol vector by ejθ' θ being a phase rotation angle. 18. The space-time-frequency block coding method as claimed in 16, comprising the step of mapping the pre-coded symbols to the transmit antennas according to the selected STFBC and transmitting the mapped symbols through the transmit antennas. 19. The space-time-frequency block coding method as claimed in claim 16, wherein each of the feedback CQIS is the average channel information of a plurality of subcarriers. 20. The space-time-frequency block coding method as claimed in claim 18, wherein each of the feedback CQIS is the average channel information of a plurality of subcarriers. 21. A method of transmitting a space-time-frequency block code (STFBC) in a transmitter with three transmit antennas, comprising the steps of: pre-coding a symbol vector of an input symbol sequence; and selecting an STFBC based on an STFBC index received from a receiver; wherein the STFBC index is obtained at the receiver according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 22. The method as claimed in claim 16, wherein the pre-coding the symbol vector of the input symbol sequence comprises, pre-coding the symbol vector of an input symbol sequence by multiplying the symbol vector by ejθ' θ being a phase rotation angle. 23. The method as claimed in claim 21, comprising the step of mapping the pre-coded symbols to the transmit antennas according to the selected STFBC and transmitting the mapped symbols through the transmit antennas. 24. A method of receiving space-time-frequency block coded symbols for receiver in a communication system having a transmitter with three transmit antennas and using a space-time-frequency block coding scheme comprising the steps of: channel-estimating a signal received through a receive antenna and outputting channel quality indicators (CQIs);and transmitting the CQIS to a space-time-frequency block code (STFBC) mapper of the transmitter; wherein the CQIs are used in the transmitter to select an STFBC according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. 25. A method of receiving space-time-frequency block coded symbols for a receiver in a communication system having a transmitter with three transmit antennas and using a space-time-frequency block coding scheme comprising the steps of: channel-estimating a signal received through a receive antenna and outputting channel quality indicators (CQIs);and transmitting a space-time-frequency block code (STFBC) index obtained using the CQIs to an STFBC mapper of a transmitter, wherein the STFBC index is obtained at the receiver according to if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix B if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3) use Martix A if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3) use Martix C where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second and third transmit antennas, respectively, select max (a, b, c) represents a maximum value among a, b and c, and the matrices A, B and C are given as where a row represents symbols for a corresponding antenna and a column represents symbols mapped with a subcarrier. ABSTRACT TITLE" A TRANSMILLER WITH THREE TRANSMIT ANTENNAS AND METHODS IN A COMMUNICATION SYSTEM USING A SPACE-TIME-FREQUENCY BLOCK CODING SCHEME" The invention relates to a space-time-frequency block coding apparatus and method in a transmitter with three transmit (Tx) antennas are provided. An input symbol sequence is transmitted through three Tx antennas according to a set method using feedback information received from a receiver or using a selected transmission matrix having regularities in order to improve the performance of an STFBC.

Full Text

WE CLAIM :
1. A transmitter with three transmit antennas in a communication system
using a space-time-frequency block coding scheme, comprising:
a pre-coder for pre-coding a symbol vector of an input symbol
sequence; and
a space-time frequency block code (STFBC) mapper for selecting an
SFTBC based on feedback channel quality indicators (CQIs) received
from a receiver, mapping the pre-coded symbols to the transmit
antennas according to the selected STFBC, and transmitting the
mapped symbols through the transmit antennas;
wherein the STFBC mapper selects the STFBC based on the feedback
CQIS according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
2. The transmitter as claimed in claim 1, wherein the pre-coder pre-
codes the symbol vector of an input symbol sequence by multiplying
the symbol vector by ejθ' θ being a phase rotation angle.
3. The transmitter as claimed in claim 1, wherein the STFBC mapper
comprises a mapper for mapping the pre-coded symbols to the transmit
antennas according to the selected STFBC and transmitting the mapped
symbols through the transmit antennas.
4. The transmitter as claimed in claim 1, wherein the selected STFBC is
transmitted to the receiver.
5. The transmitter as claimed in claim 3, wherein the selected STFBC is
transmitted to the receiver.

6. The transmitter as claimed in claim 1, wherein each of the feedback
CQIs is the average channel information of a plurality of subcarriers.
7. The transmitter as claimed in claim 3, wherein each of the feedback
CQIs is the average channel information of a plurality of subcarriers.
8. A transmitter with three transmit antennas in a communication system
using a space-time-frequency block coding scheme, comprising:
a pre-coder for pre-coding a symbol vector of an input symbol
sequence; and
a space-time-frequency block code (STFBC) mapper for selecting an
STFBC based on feedback channel quality indicators (CQIS) received
from a receiver, mapping the pre-coded symbols to the transmit
antennas according to the selected STFBC, and transmitting the
mapped symbols through the transmit antennas;
wherein the STFBC mapper selects the STFBC based on the feedback
CQIs according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
9. The transmitter as claimed in claim 8, wherein the pre-coder pre-
codes the symbol vector of an input symbol sequence by multiplying
the symbol vector by ejθ, θ being a phase rotation angle.
10. The transmitter as claimed in claim 8, wherein the STFBC mapper
comprises a mapper for mapping the pre-coded symbols to the
transmit antennas according to the selected STFBC, and transmitting
the mapped symbols through the transmit antennas.
11. The transmitter as claimed in claim 8, wherein the selected STFBC is
transmitted to the receiver.
12. The transmitter as claimed in claim 10, wherein the selected STFBC is
transmitted to the receiver.

13. A receiver in a communication system having a transmitter with three
transmit antennas and using a space-time-frequency block coding
scheme, comprising:
a channel estimator for channel-estimating a signal received through a
receive antenna and outputting channel quality indicators (CQIs); and
a feedback transmitter for transmitting the CQIs to a space-time-
frequency block code (STFBC) mapper of a transmitter;
wherein the CQIs are used in the transmitter to select an STFBC
according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
14. The receiver as claimed in claim 13, wherein each of the CQIS is the
average channel information of a plurality of subcarriers.
15. A receiver in a communication system having a transmitter with three
transmit antennas and using a space time frequency block coding
scheme, comprising:
a channel estimator for channel-estimating a signal received through a
receive antenna and outputting channel quality indicators (CQIs); and
a feedback transmitter for transmitting a space-time-frequency block
code (STFBC) index obtained using the CQIS to an STFBC mapper of a
transmitter;

wherein the STFBC index is obtained at the receiver according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.

16. A space-time-frequency block coding method in a transmitter with
three transmit antennas, comprising the steps of:
pre-coding a symbol vector of an input symbol sequence; and
selecting a space-time-frequency block code (STFBC) based on
feedback channel quality indicators (CQIs) received from a receiver, for
mapping of the pre-coded symbols;
wherein the STFBC selecting step comprises the step of selecting the
STFBC based on the feedback CQIs according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
17. The space-time-frequency block coding method as claimed in claim 16,
wherein the pre-coding the symbol vector of the input symbol
sequence comprises, pre-coding the symbol vector of an input symbol
sequence by multiplying the symbol vector by ejθ' θ being a phase
rotation angle.
18. The space-time-frequency block coding method as claimed in 16,
comprising the step of mapping the pre-coded symbols to the transmit
antennas according to the selected STFBC and transmitting the
mapped symbols through the transmit antennas.
19. The space-time-frequency block coding method as claimed in claim 16,
wherein each of the feedback CQIS is the average channel information
of a plurality of subcarriers.

20. The space-time-frequency block coding method as claimed in claim 18,
wherein each of the feedback CQIS is the average channel information
of a plurality of subcarriers.
21. A method of transmitting a space-time-frequency block code (STFBC)
in a transmitter with three transmit antennas, comprising the steps of:
pre-coding a symbol vector of an input symbol sequence; and
selecting an STFBC based on an STFBC index received from a receiver;
wherein the STFBC index is obtained at the receiver according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQl_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
22. The method as claimed in claim 16, wherein the pre-coding the symbol
vector of the input symbol sequence comprises, pre-coding the symbol
vector of an input symbol sequence by multiplying the symbol vector
by ejθ' θ being a phase rotation angle.
23. The method as claimed in claim 21, comprising the step of mapping
the pre-coded symbols to the transmit antennas according to the
selected STFBC and transmitting the mapped symbols through the
transmit antennas.
24. A method of receiving space-time-frequency block coded symbols for
receiver in a communication system having a transmitter with three
transmit antennas and using a space-time-frequency block coding
scheme comprising the steps of:

channel-estimating a signal received through a receive antenna and
outputting channel quality indicators (CQIs);and
transmitting the CQIS to a space-time-frequency block code (STFBC)
mapper of the transmitter;
wherein the CQIs are used in the transmitter to select an STFBC
according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.
25. A method of receiving space-time-frequency block coded symbols for a
receiver in a communication system having a transmitter with three
transmit antennas and using a space-time-frequency block coding
scheme comprising the steps of:
channel-estimating a signal received through a receive antenna and
outputting channel quality indicators (CQIs);and
transmitting a space-time-frequency block code (STFBC) index
obtained using the CQIs to an STFBC mapper of a transmitter,
wherein the STFBC index is obtained at the receiver according to
if CQI_ ant1=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix B
if CQI_ant2=select max (CQI_ant1, CQI_ant2, CQI_ant3)
use Martix A
if CQ1_ant3=select max(CQI_ant1, CQI_ant2, CQI_ant3)
use Martix C
where CQI_ant1, CQI_ant2, CQI_ant3 represent CQIS for first, second
and third transmit antennas, respectively, select max (a, b, c)
represents a maximum value among a, b and c, and the matrices A, B
and C are given as

where a row represents symbols for a corresponding antenna and a
column represents symbols mapped with a subcarrier.

ABSTRACT

TITLE" A TRANSMILLER WITH THREE TRANSMIT
ANTENNAS AND METHODS IN A COMMUNICATION
SYSTEM USING A SPACE-TIME-FREQUENCY
BLOCK CODING SCHEME"
The invention relates to a space-time-frequency block coding apparatus and
method in a transmitter with three transmit (Tx) antennas are provided. An input
symbol sequence is transmitted through three Tx antennas according to a set
method using feedback information received from a receiver or using a selected
transmission matrix having regularities in order to improve the performance of
an STFBC.

A TRANSMITTER AND A RECEIVER IN A COMMUNICATION SYSTEM FOR INCREASED PERFORMANCE IN SPACE-TIME FREQUENCY BLOCK CODING AND METHODS THEREFORE

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