Enhanced lattice reduction systems and methods
AssigneeGeorgia Tech Research Corporation
InventorsQi Zhou, Xiaoli Ma
Life of this patent
Estimating the term…
Abstract
An exemplary embodiment of the present invention provides a lattice reduction method comprising obtaining a preliminary estimate of a transformation matrix, generating a covariance matrix based on the preliminary estimate of the transformation matrix, reducing diagonal elements of the covariance matrix to generate a unimodular transformation matrix, and using the unimodular transformation matrix to obtain an estimate of an input.
Claims20
A method of estimating an input in a MIMO communication system comprising:
- receiving a transmitted signal at a plurality of antennas, the signal containing the input, linearly transformed by a channel matrix;
- calculating, by a processor, a preliminary estimate of the channel matrix;
- generating, by a processor, a covariance matrix based on the preliminary estimate of the channel matrix;
- generating, by the processor, a unimodular transformation matrix by reducing diagonal elements of the covariance matrix {tilde over (C)};
- obtaining, by the processor, an estimate of the input by applying the unimodular transformation matrix to the received signal;
- detecting a quadrature amplitude modulation (QAM) symbol using the estimate of the input;
- and
- outputting an output signal corresponding to the QAM symbol,
- wherein reducing diagonal elements of the covariance matrix comprises selecting an index pair (i,k) and updating a corresponding kth column and kth row of the covariance matrix according to
- λ
- i
- ,
- k
- =
- -
- [
- C
- ~
- i
- ,
- k
- C
- ~
- i
- ,
- i
- ]
- ,
- wherein {tilde over (C)}i,k and {tilde over (C)}i,i are elements of the covariance matrix.
A MIMO communication system comprising:
- a plurality of antennas configured to receive a transmitted signal, the signal containing an input linearly transformed by a channel matrix;
- a processor;
- and
- logic stored in a non-transitory computer readable media that, when executed by the processor, is configured to:
- calculate a preliminary estimate of the channel matrix;
- generate a covariance matrix based on the preliminary estimate of the channel matrix;
- generate a unimodular transformation matrix by reducing diagonal elements of the covariance matrix;
- obtain an estimate of the input by applying the unimodular transformation matrix to the received signal;
- detect a quadrature amplitude modulation (QAM) symbol using the estimate of the input;
- and
- output an output signal corresponding to the QAM symbol,
- wherein reducing diagonal elements of the covariance matrix comprises selecting an index pair (i,k) and updating a corresponding kth column and kth row of the covariance matrix according to
- λ
- i
- ,
- k
- =
- -
- [
- C
- ~
- i
- ,
- k
- C
- ~
- i
- ,
- i
- ]
- ,
- wherein {tilde over (C)}i,k and {tilde over (C)}i,i are elements of the covariance matrix.
A non-transitory computer-readable medium storing computer executable instructions that, when executed by one or more computing devices, configure the one or more computing devices to perform operations comprising:
- receiving a transmitted signal at a plurality of antennas of a MIMO communication system, the signal containing an input linearly transformed by a channel matrix;
- obtaining, by a processor, a preliminary estimate of the channel matrix;
- generating, by a processor, a covariance matrix based on the preliminary estimate of the channel matrix;
- generating, by a processor, a unimodular transformation matrix by reducing diagonal elements of the covariance matrix;
- obtaining, by a processor, an estimate of the input by applying the unimodular transformation matrix to the received signal;
- detecting a quadrature amplitude modulation (QAM) symbol using the estimate of the input;
- and
- outputting an output signal corresponding to the QAM symbol,
- wherein reducing diagonal elements of the covariance matrix comprises selecting an index pair (i,k) and updating a corresponding kth column and kth row of the covariance matrix according to
- λ
- i
- ,
- k
- =
- -
- [
- C
- ~
- i
- ,
- k
- C
- ~
- i
- ,
- i
- ]
- ,
- wherein {tilde over (C)}i,k and {tilde over (C)}i,i are elements of the covariance matrix.
Dependencies are inferred from the claim text.