HIGH-SPEED IN-MEMORY QR DECOMPOSITION USING FAST PLANE ROTATIONS
A system and method for processing an input matrix and a MIMO receiver employing the system or the method. In one embodiment, the system includes: (1) a transformer configured to receive a frame of complex data representing only some elements of an input matrix and perform a fast plane rotation on the complex data to yield rotated data and (2) a matrix updater coupled to the transformer and configured to update a memory configured to contain an output matrix with the rotated data. In one embodiment, the system and method are to estimate and mitigate alien cross-talk experienced in a vectored DSL communication system.
1 . A system for processing an input matrix, comprising:
a transformer configured to receive a frame of complex data representing only some elements of an input matrix and perform a fast plane rotation on said complex data to yield rotated data; and
a matrix updater coupled to said transformer and configured to update a memory configured to contain an output matrix with said rotated data.
2 . The system as recited in claim 1 further comprising an initial decomposer configured to compute an initial upper-triangular matrix and cause said initial upper-triangular matrix to be stored in said memory as said output matrix.
3 . The system as recited in claim 2 wherein said initial decomposer, said transformer and said matrix updater cooperate to perform a QR decomposition of said input matrix.
4 . The system as recited in claim 1 wherein said transformer is configured to receive multiple frames of complex data over time.
5 . The system as recited in claim 1 wherein said transformer is further configured to scale said fast plane rotation dynamically.
6 . The system as recited in claim 1 wherein said transformer is further configured to perform said fast plane rotation without creating a temporary vector copy of said frame.
7 . The system as recited in claim 1 wherein said matrix updater is further configured to overwrite frames of complex data that said transformer has processed.
8 . A method of processing an input matrix, comprising:
receiving a frame of complex data representing only some elements of an input matrix;
performing a fast plane rotation on said complex data to yield rotated data; and
updating a memory configured to contain an output matrix with said rotated data.
9 . The method as recited in claim 8 further comprising:
computing an initial upper-triangular matrix; and
causing said initial upper-triangular matrix to be stored in said memory as said output matrix.
10 . The method as recited in claim 9 wherein said performing and said updating constitute QR decomposing said input matrix.
11 . The method as recited in claim 8 further comprising carrying out said receiving multiple times over time.
12 . The method as recited in claim 8 further comprising scaling said fast plane rotation dynamically.
13 . The method as recited in claim 8 further comprising performing said fast plane rotation without creating a temporary vector copy of said frame.
14 . The method as recited in claim 8 further comprising overwriting processed frames of complex data.
15 . A MIMO receiver, comprising:
a receive chain including alien crosstalk mitigation circuitry having a spatial correlation estimator and an alien crosstalk canceller, configured to receive a frame of complex data representing only some elements of an input matrix and including:
an initial decomposer configured to compute an initial upper-triangular matrix and cause said initial upper-triangular matrix to be stored in a memory as an output matrix,
a transformer configured to perform a fast plane rotation on said complex data to yield rotated data, and
a matrix updater coupled to said transformer and configured to update said memory with said rotated data.
16 . The MIMO receiver as recited in claim 15 wherein said initial decomposer, said transformer and said matrix updater cooperate to perform a QR decomposition of said input matrix.
17 . The MIMO receiver as recited in claim 15 wherein said transformer is configured to receive multiple frames of complex data over time.
18 . The MIMO receiver as recited in claim 15 wherein said transformer is further configured to scale said fast plane rotation dynamically.
19 . The MIMO receiver as recited in claim 15 wherein said transformer is further configured to perform said fast plane rotation without creating a temporary vector copy of said frame.
20 . The MIMO receiver as recited in claim 15 wherein said matrix updater is further configured to overwrite frames of complex data that said transformer has processed.
21 . A MIMO transmitter, comprising:
a transmit chain configured to receive a frame of complex data representing only some elements of an input matrix and including:
a transformer configured to perform a fast plane rotation on said complex data to yield rotated data, and
a matrix updater coupled to said transformer and configured to update a memory configured to contain an output matrix with said rotated data.
22 . The MIMO transmitter as recited in claim 21 further comprising an initial decomposer configured to compute an initial upper-triangular matrix and cause said initial upper-triangular matrix to be stored in said memory as said output matrix.
23 . The MIMO transmitter as recited in claim 22 wherein said initial decomposer, said transformer and said matrix updater cooperate to perform a QR decomposition of said input matrix.
24 . The MIMO transmitter as recited in claim 21 wherein said transformer is configured to receive multiple frames of complex data over time.
25 . The MIMO transmitter as recited in claim 21 wherein said transformer is further configured to scale said fast plane rotation dynamically.
26 . The MIMO transmitter as recited in claim 21 wherein said transformer is further configured to perform said fast plane rotation without creating a temporary vector copy of said frame.
27 . The MIMO transmitter as recited in claim 21 wherein said matrix updater is further configured to overwrite frames of complex data that said transformer has processed.