Method, system and receiver in receiving a multi-carrier transmission
View Patent ↗Mobile handheld terminals receiving DVB transmission require relatively low power consumption and TDM based transmission can be used to reduce power of the terminals. In order find pilot carrier position at least two symbols are accessed which are adapted to establish a correspondence pattern for pilot carriers in a matrix of the at least two symbols. Carriers of the first symbol are correlated with the corresponding carriers of the second symbol within the matrix for determining a correlation maximum for indicating a pilot carrier position.
1. A method, comprising:
receiving into an apparatus a multi-carrier transmission time-sliced into bursts, wherein the multicarrier transmission comprises one or more symbols each including a plurality of carriers;
establishing in the apparatus a correspondence pattern matrix for pilot carriers by accessing at least two symbols from the multi-carrier transmission;
correlating in the apparatus carriers of the first symbol with the corresponding carriers of the second symbol within the matrix;
determining in the apparatus a correlation maximum indicating a pilot carrier position; and
synchronizing the apparatus to the multi-carrier transmission bursts by finding the index of received symbols based on the pilot carrier position.
2. The method according to claim 1 , wherein the accessed symbols are selected so that the correspondence pattern is adapted to be established between pilot carriers of the symbols for certain carrier positions within the matrix of the symbols.
3. The method according to claim 1 , wherein the step of accessing comprises:
receiving the first symbol of the transmission,
delaying the first symbol in relation to the second symbol, wherein the symbols are adapted to establish the correspondence pattern for pilot carriers in the matrix of the two symbols.
4. The method according to claim 1 , wherein the accessed symbols comprise currently a received symbol and a certain predetermined other symbol following the currently received symbol.
5. The method according to claim 4 , wherein the accessed symbols comprise a currently received symbol and a certain predetermined other symbol following the currently received symbol so that the correspondence pattern is adapted to be established between pilot carriers of the symbols for certain carrier positions within the matrix of the symbols.
6. The method according to claim 4 , wherein the certain predetermined other symbol is the fourth symbol received by the apparatus as determined beginning from the currently received symbol.
7. The method according to claim 1 , wherein the step of correlating comprises:
performing a first correlation between first possible pilot carrier positions of the first symbol and first possible pilot carrier positions of the second symbol,
performing a second correlation between second possible pilot carrier positions of the first symbol and second possible pilot carrier positions of the second symbol,
performing a third correlation between third possible pilot carrier positions of the first symbol and third possible pilot carrier positions of the second symbol,
performing a fourth correlation between fourth possible pilot carrier positions of the first symbol and fourth possible pilot carrier positions of the second symbol,
detecting the correlation maximum magnitude from the first, second, third, and fourth correlations for indicating the current scattered pilot raster position.
8. The method according to claim 7 , wherein the first correlation is calculated based on the following formulae:
C
1
(
n
)
=
∑
p
=
0
p
max
S
(
n
,
12
p
+
12
)
·
S
*
(
n
-
4
,
12
p
+
12
)
,
wherein S(n,c) denotes c-th subcarrier of the current symbol and p max denotes last index of the current symbol, which depends on the used mode of the transmission.
9. The method according to claim 7 , wherein the second correlation is calculated based on the following formulae:
C
2
(
n
)
=
∑
p
=
0
p
max
S
(
n
,
12
p
+
3
)
·
S
*
(
n
-
4
,
12
p
+
3
)
,
wherein S(n,c) denotes c-th subcarrier of the current symbol and p max denotes last index of the current symbol, which depends on the used mode of the transmission.
10. The method according to claim 7 , wherein the third correlation is calculated based on the following formulae:
C
3
(
n
)
=
∑
p
=
0
p
max
S
(
n
,
12
p
+
6
)
·
S
*
(
n
-
4
,
12
p
+
6
)
,
wherein S(n,c) denotes c-th subcarrier of the current symbol and p max denotes last index of the current symbol, which depends on the used mode of the transmission.
11. The method according to claim 7 , wherein the fourth correlation is calculated based on the following formulae:
C
4
(
n
)
=
∑
p
=
0
p
max
S
(
n
,
12
p
+
9
)
·
S
*
(
n
-
4
,
12
p
+
9
)
,
wherein S(n,c) denotes c-th subcarrier of the current symbol and p max denotes last index of the current symbol, which depends on the used mode of the transmission.
12. The method according to claim 7 , wherein the first correlation is calculated based on the following formulae:
C
1
(
n
)
=
∑
p
=
0
p
max
S
(
n
,
12
p
)
·
S
*
(
n
-
4
,
12
p
)
,
wherein S(n,c) denotes c-th subcarrier of the current symbol and p max denotes last index of the current symbol, which depends on the used mode of the transmission.
13. The method according to claim 7 , wherein in the step of detecting the correlation maximum magnitude is based on the following formulae:
C max (n)=max(C p (n)); pε{1,2,3,4}, wherein C p (n) denotes the first, second, third, and fourth correlations, p is adapted to determine pilot carrier positions for identifying a certain symbol, and
the current scattered pilot raster position (SPRP) is found based on the following formulae:
SPRP
(
n
)
=
arg
max
p
(
C
p
(
n
)
)
;
p
∈
{
1
,
2
,
3
,
4
}
,
wherein the C p (n) denotes the first, second, third, and fourth correlations, p is adapted to determine pilot carrier positions for identifying a certain symbol.
14. The method according to claim 1 , wherein the multi-carrier transmission comprises orthogonal frequency-division multiplexing (OFDM) transmission using time slicing, the one or more symbols comprise OFDM symbols and the plurality of carriers comprise data carriers and scattered pilot carriers.
15. The method according to claim 1 , wherein the multi-carrier transmission comprises digital video broadcast (DVB) transmission using time slicing based on bursts, and synchronization into the bursts is adapted to be based on the indicated pilot position for finding an indication indicating the orthogonal frequency-division multiplexing (OFDM) symbol.
16. A system, comprising:
means for receiving into an apparatus a multi-carrier transmission time-sliced into bursts, wherein the multicarrier transmission comprises one or more symbols each including a plurality of carriers;
means for establishing in the apparatus a correspondence pattern matrix for pilot carriers by accessing at least two symbols from the multi-carrier transmission;
means for correlating in the apparatus carriers of the first symbol with the corresponding carriers of the second symbol within the matrix for determining a correlation maximum for indicating a pilot carrier position; and
means for synchronizing the apparatus to the multi-carrier transmission bursts by finding the index of received symbols based on the pilot carrier position.
17. A receiver, comprising:
a signal receiver configured to receive a multi-carrier transmission time-sliced into bursts, wherein the multicarrier transmission comprises one or more symbols each including a plurality of carriers;
a Fast Fourier Transform (FFT) block configured to FFT transform the received transmission for obtaining at least two symbols of the transmission;
a delay block configured to delay an obtained first symbol to obtain another symbol, wherein a matrix, comprising the symbols and their respective carriers, is adapted to establish a correspondence pattern for pilot carriers of the first symbol with pilot carriers of the other symbol within the matrix;
a correlator configured to correlate carriers of the symbol with the corresponding carriers of the another symbol within the matrix;
an accumulator configured to accumulate correlation results obtained from the correlator;
a decision block configured to detect a correlation maximum from the correlation results for indicating a pilot carrier position; and
a synchronizer configured to synchronize the receiver to the multi-carrier transmission bursts by finding the index of received symbols based on the pilot carrier position.
18. The receiver according to claim 17 , wherein computational resources for performing the operations of at least the correlator and the decision block comprises the same computational resources which are configured to perform a post-FFT acquisition in the receiver.
19. The receiver according to claim 17 , wherein a buffer of the receiver is configured to contain the delay block, the correlator, the accumulator, and the decision block.