Method for the soft bit metric calculation with linear MIMO detection for LDPC codes
First Claim
Patent Images
1. A method of soft bit metric calculation for received data signals via a channel in a telecommunications receiver utilizing Low Density Parity Check (LDPC) decoding, comprising:
- detecting data symbols in the received signals by applying a linear Multiple-Input Multiple-Output (MIMO) detection, wherein the linear MIMO detection comprises determining distances between the detected data symbols and constellation points;
determining a noise variance of the channel;
calculating the soft bit metrics as a function of the distances between the detected data symbols and the constellation points, and calculating a channel noise variance matrix E[vvH], wherein the distances are divided by the noise variance, wherein calculating the soft bit metrics further includes;
selecting diagonal elements of the channel noise variance matrix E[vvH], andcalculating the soft bit metrics as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter and WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of V.
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Abstract
A MIMO receiver implements a method for the soft bit metric calculation with linear MIMO detection for LDPC codes, after linear matrix inversion MIMO detection. In the receiver, a detector detects the estimated symbol and the noise variance. Further, a soft metric calculation unit computes the distance between the estimated symbol and the constellation point, and then divides the distance by the noise variance to determine the soft bit metrics.
77 Citations
33 Claims
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1. A method of soft bit metric calculation for received data signals via a channel in a telecommunications receiver utilizing Low Density Parity Check (LDPC) decoding, comprising:
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detecting data symbols in the received signals by applying a linear Multiple-Input Multiple-Output (MIMO) detection, wherein the linear MIMO detection comprises determining distances between the detected data symbols and constellation points; determining a noise variance of the channel; calculating the soft bit metrics as a function of the distances between the detected data symbols and the constellation points, and calculating a channel noise variance matrix E[vvH], wherein the distances are divided by the noise variance, wherein calculating the soft bit metrics further includes; selecting diagonal elements of the channel noise variance matrix E[vvH], and calculating the soft bit metrics as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter and WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of V.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A telecommunications receiver, comprising:
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a detector that detects data symbols in received signals by determining distances between received signal points and constellation points, and determines channel noise variance; a metric calculator that calculates soft bit metrics for the received signals via a channel, as a function of the distances and the noise variance, wherein the distances are divided by the noise variance, wherein the metric calculator calculates the soft bit metrics by; selecting diagonal elements σ
v2 of the noise variance matrix E[vvH],calculating the soft bit metrics as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter and WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v; anda decoder that performs LDPC decoding of the received signals using the soft bit metrics. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A wireless communication receiver, comprising:
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a detector configured to detect symbols by determining distances between received signal points and constellation points, and to determine channel noise variance in a received data signal by applying a linear MIMO detection; a metric calculator configured to select diagonal elements σ
v2 of a noise variance matrix E[vvH] and calculate soft bit metrics for the received data signal via a channel by selecting the diagonal elements σ
v2 of the noise variance matrix E[vvH] as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v.- View Dependent Claims (25, 26, 27, 28)
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29. A method of soft bit metric calculation for received data signals via a channel in a telecommunications receiver utilizing LDPC decoding, comprising:
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detecting data symbols in the received signals by applying a linear MIMO detection, wherein the linear MIMO detection comprises determining distances between the detected data symbols and constellation points; determining a noise variance of the channel; calculating the soft bit metrics as a function of the distances between the detected data symbols and the constellation points, and calculating a channel noise variance matrix E[vvH], wherein the distances are divided by the noise variance, said calculating further includes selecting the diagonal elements σ
v2 of the noise variance matrix E[vvH] as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},where W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v,wherein the channel is defined by a NrxNt channel matrix H in a MIMO system having a receiver with Nt transmitter antennas and Nr receiver antennas, x is the Ntx1 transmitted signal vector, the received symbol is represented by a Nrx1 received symbol vector y=Hx+n, n represents a Nrx1 noise vector, the method further comprising applying the linear filter W to the received symbols y to compute estimated symbols {circumflex over (x)} as;
{circumflex over (x)}=Wy=WHx+Wn,where W=(HHH+σ
n2I)−
1HH with MMSE criterion, where HH is a pseudo-inverse of H.
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30. A telecommunications receiver, comprising:
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a detector that detects data symbols in received signals by determining distances between received signal points and constellation points, and determines noise variance of a channel; a metric calculator that calculates soft bit metrics for the received signals via the channel, as a function of the distances and the noise variance, wherein the distances are divided by the noise variance, said calculator further selects the diagonal elements σ
v2 of a noise variance matrix E[vvH] as a function of the distances and σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},where W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v; anda decoder that performs LDPC decoding of the received signals using the soft bit metrics, wherein the channel is defined by a NrxNt channel matrix H in a MIMO system having a receiver with Nt transmitter antennas and Nr receiver antennas, x is the Ntx1 transmitted signal vector, the received symbol is represented by a Nrx1 received symbol vector y=Hx+n, n represents a Nrx1 noise vector, such that the detector applies the linear filter W to the received symbols y to compute estimated symbols {circumflex over (x)} as;
{circumflex over (x)}=Wy=WHx+Wn,where W=(HHH+σ
n2I)−
1HH with MMSE criterion and HH is a pseudo-inverse of H.
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31. A method of soft bit metric calculation for received signals via a channel in a telecommunications receiver utilizing LDPC decoding, comprising:
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detecting data symbols in the received signals by applying a linear MIMO detection, wherein the linear MIMO detection comprises determining distances between the detected data symbols and constellation points; determining a noise variance of the channel; calculating the soft bit metrics as a function of the distances between the detected data symbols and the constellation points, and calculating a channel noise variance matrix E[vvH], wherein the distances are divided by the noise variance, wherein calculating the soft bit metrics further includes; selecting diagonal elements σ
v2 of the channel noise variance matrix E[vvH] andcalculating the soft bit metrics as a function of the distances and the diagonal elements σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v.
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32. A telecommunications receiver, comprising:
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a detector that detects data symbols in signals received via a channel by determining distances between received signal points and constellation points, and determines noise variance of the channel; a metric calculator that calculates soft bit metrics for the received signals, as a function of the distances and the noise variance, wherein the distances are divided by the noise variance, wherein the metric calculator calculates the soft bit metrics by; selecting the diagonal elements σ
v2 of a channel noise variance matrix E[vvH],calculating the soft bit metrics as a function of the distances and the diagonal elements σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v; anda decoder that performs LDPC decoding of the received signals using the soft bit metrics.
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33. A wireless communication receiver, comprising:
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a detector configured for detecting symbols by determining distances between received signal points and constellation points, and for determining channel noise variance in a received data signal by applying a linear MIMO detection; a metric calculator configured for selecting diagonal elements σ
v2 of a noise variance matrix E[vvH] and for calculating soft bit metrics for the received data signal via a channel by selecting the diagonal elements σ
v2 of the noise variance matrix E[vvH], and calculating the soft bit metrics as a function of the distances and the diagonal elements σ
v2, where the diagonal elements σ
v2 is defined as;
σ
v2=E[diag{vvH}]
=σ
n2diag{WWH},W is a linear filter, WH is a pseudo-inverse of W, σ
n2 represents the noise variance and v is a new noise term and vH is a pseudo-inverse of v.
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Specification