Method of decoding a received SC-FDMA symbol in a receiver in a OFDM communication system, a receiver, an apparatus, an OFDM communication system and a computer program product
View Patent ↗A method of decoding a received SC-FDMA symbol in a receiver in a OFDM communication system is described. The method comprises calculating an approximate constellation energy {circumflex over (K)} from channel matrices H i for all subcarriers i, a noise covariance matrix S, and a data signal power matrix C associated with the OFDM symbol, an approximate constellation energy {circumflex over (K)}. The approximate constellation energy {circumflex over (K)} is calculated according to: Q i = H i H S - 1 H i ; Q ^ = 1 N sc ∑ i = 0 N sc - 1 Q i ; K ^ = diag ( ( Q ^ + C - 1 ) - 1 Q ^ ) The method further comprises decoding the received symbol using at least the associated approximate constellation energy {circumflex over (K)}. Also, a receiver, an apparatus, an OFDM communication system and a computer program product for such decoding are described.
1. A method of decoding a received SC-FDMA symbol in a receiver in a OFDM communication system, the method comprising:
determining, in a channel and noise estimator of a frequency domain processor of the receiver, the channel matrices H i for all subcarriers i from at least one received SC-FDMA pilot symbol as channel matrix estimates,
determining, in the channel and noise estimator of the frequency domain processor of the receiver, the noise covariance matrix from the at least one received SC-FDMA pilot symbol,
calculating, in a constellation statistics calculator of the frequency domain processor of the receiver, an approximate constellation energy {circumflex over (K)} according to:
Q
i
=
H
i
H
S
-
1
H
i
Q
^
=
1
N
sc
∑
i
=
0
N
sc
-
1
Q
i
K
^
=
diag
(
(
Q
^
+
C
-
1
)
-
1
Q
^
)
from channel matrices H i for all subcarriers i of N sc subcarriers of an allocation, a noise covariance matrix S, and a data signal power matrix C associated with the received SC-FDMA symbol, and
decoding, in a demodulator of the receiver, the received symbol using the associated approximate constellation energy {circumflex over (K)}.
2. The method of claim 1 , further comprising calculating an approximate constellation variance Û according to:
Û=diag (( {circumflex over (Q)}=C −1 ) −1 )
and wherein decoding the received symbol further uses approximate constellation variance Û.
3. The method of claim 1 , wherein the decoding comprises a Turbo decoding or a maximum likelihood Euclidian based decoding.
4. The method of claim 1 , wherein the receiver is an LTE receiver and the OFDM communication system is an LTE communication system.
5. The method of claim 1 , the method further comprising determining the data signal power matrix C from the at least one received SC-FDMA symbol.
6. A constellation statistics calculator (CSCE) for a receiver in a OFDM communication system, the constellation statistics calculator (CSCE) arranged to calculate an approximate constellation energy {circumflex over (K)} according to:
Q
i
=
H
i
H
S
-
1
H
i
Q
^
=
1
N
sc
∑
i
=
0
N
sc
-
1
Q
i
K
^
=
diag
(
(
Q
^
+
C
-
1
)
-
1
Q
^
)
from channel matrices H i for all subcarriers i of N sc subcarriers of an allocation, a noise covariance matrix S, and a data signal power matrix C associated with a received SC-FDMA symbol, wherein the associated approximate constellation energy {circumflex over (K)}is used in the receiver to decode the received SC-FDMA symbol.
7. A constellation statistics calculator (CSCE) of claim 6 , further arranged to calculate an approximate constellation variance Û according to:
Û=diag (( {circumflex over (Q)}=C −1 ) −1 ).
8. A receiver (RECE) comprising a constellation statistics calculator (CSCE) of claim 6 .
9. The receiver of claim 8 , wherein the receiver is an LTE receiver.
10. An OFDM communication system comprising the receiver of claim 9 .
11. The method of claim 2 , further comprising:
determining the channel matrices H i for all subcarriers i from at least one received SC-FDMA pilot symbol as channel matrix estimates, and
determining the noise covariance matrix from the at least one received SC-FDMA pilot symbol.
12. The method of claim 3 , further comprising:
determining the channel matrices H i for all subcarriers i from at least one received SC-FDMA pilot symbol as channel matrix estimates, and
determining the noise covariance matrix from the at least one received SC-FDMA pilot symbol.
13. The method of claim 4 , further comprising:
determining the channel matrices H i for all subcarriers i from at least one received SC-FDMA pilot symbol as channel matrix estimates, and
determining the noise covariance matrix from the at least one received SC-FDMA pilot symbol.