Simultaneous PMD compensation and chromatic dispersion compensation using LDPC coded OFDM
First Claim
Patent Images
1. A method comprising the steps of:
- estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission;
performing channel estimation to determine channel estimates in reception of the LDPC encoded OFDM signal; and
obtaining channel information for use in detection and decoding of the LDPC encoded signal, wherein the estimated QAM symbols are related to the channel distortion introduced by fiber optical signals, phase shift of the QAM symbols due to chromatic dispersion and self-phase modulation and wherein a λ
-configuration, denoted as t-(v,k,{0, 1, . . . λ
}), is a collection of k-subsets (blocks) of a v-set V such that every t-subset of V is contained in at most λ
of the blocks and let λ
1- and λ
2-configurations, denoted as t-(v1,k1,{0, 1, . . . , λ
1}) and t-(v2,k2,{0, 1, . . . , λ
2}) be given, denote the number of blocks in λ
1- and λ
2-configurations by b1 and b2, respectively; and
the corresponding set of blocks by B1 and B2, respectively, the v1v2-elements in the product configuration are ordered pair of elements (e1,e2), with e1 belonging to B1 and e2 belonging to B2, b=└
b1/k1┘
·
└
b2/k2┘
blocks of a product configuration are obtained as follows, with └
┘
denoted the largest integer less than or equal to the enclosed quantity, let the blocks from B1 be grouped into └
b1/k1┘
classes of k1 blocks each, the first block in a product configuration is obtained as a k1k2-block of ordered pair of elements ((α
1,β
1), . . . , (α
1,β
k2), . . . , (α
k1,β
1), . . . , (α
k1,β
k2)), with α
i (i=1, . . . , k1) belonging to the first block of B1, and Bi (i=1, . . . , k2) belonging to the first block in B2 and the LDPC encoding comprises a first class code rate obtained by taking one block from the first class in B1 at the time and one block in B2 out of the first k2 blocks and creating a product block.
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Abstract
A method includes estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission, performing channel estimation by training sequence to determine channel coefficients in reception of the LDPC encoded OFDM signal; and obtaining channel information detection and decoding of the LDPC encoded signal.
22 Citations
16 Claims
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1. A method comprising the steps of:
-
estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission; performing channel estimation to determine channel estimates in reception of the LDPC encoded OFDM signal; and obtaining channel information for use in detection and decoding of the LDPC encoded signal, wherein the estimated QAM symbols are related to the channel distortion introduced by fiber optical signals, phase shift of the QAM symbols due to chromatic dispersion and self-phase modulation and wherein a λ
-configuration, denoted as t-(v,k,{0, 1, . . . λ
}), is a collection of k-subsets (blocks) of a v-set V such that every t-subset of V is contained in at most λ
of the blocks and let λ
1- and λ
2-configurations, denoted as t-(v1,k1,{0, 1, . . . , λ
1}) and t-(v2,k2,{0, 1, . . . , λ
2}) be given, denote the number of blocks in λ
1- and λ
2-configurations by b1 and b2, respectively; and
the corresponding set of blocks by B1 and B2, respectively, the v1v2-elements in the product configuration are ordered pair of elements (e1,e2), with e1 belonging to B1 and e2 belonging to B2, b=└
b1/k1┘
·
└
b2/k2┘
blocks of a product configuration are obtained as follows, with └
┘
denoted the largest integer less than or equal to the enclosed quantity, let the blocks from B1 be grouped into └
b1/k1┘
classes of k1 blocks each, the first block in a product configuration is obtained as a k1k2-block of ordered pair of elements ((α
1,β
1), . . . , (α
1,β
k2), . . . , (α
k1,β
1), . . . , (α
k1,β
k2)), with α
i (i=1, . . . , k1) belonging to the first block of B1, and Bi (i=1, . . . , k2) belonging to the first block in B2 and the LDPC encoding comprises a first class code rate obtained by taking one block from the first class in B1 at the time and one block in B2 out of the first k2 blocks and creating a product block. - View Dependent Claims (2, 3, 4, 5, 6)
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-
7. A method comprising:
-
estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission; performing channel estimation to determine channel estimates in reception of the LDPC encoded OFDM signal; and obtaining channel information for use in detection and decoding of the LDPC encoded signal, wherein λ
-configuration, denoted as t-(v,k,{0, 1, . . . , λ
}), is a collection of k-subsets (blocks) of a v-set V such that every t-subset of V is contained in at most λ
of the blocks and let λ
1 and λ
2 configurations, denoted as t-(v1,k1,{0, 1, . . . , λ
1}) and t-(v2,k2,{0, 1, . . . , λ
2}), be given, denote the number of blocks in λ
1 and λ
2-configurations by b1 and b2, respectively; and
the corresponding set of blocks by B2 and B2, respectively, the v1v2-elements in the product configuration are ordered pair of elements (e1,e2), with e1 belonging to B1 and e2 belonging to B2, b=└
b1/k1┘
·
└
b2/k2┘
blocks of a product configuration are obtained as follows, with └
┘
denoted the largest integer less than or equal to the enclosed quantity, let the blocks from B1 be grouped into └
b1/k1┘
classes of k1 blocks each, the first block in a product configuration is obtained as a k1k2-block of ordered pair of elements ((α
1β
1), . . . , (α
1,β
k2), . . . , (α
k1,β
1), . . . , (α
k1,β
k2)), with α
i (i=1, . . . , k1) belonging to the first block of B1, and β
i (i=1, . . . , k2) belonging to the first block in B2 and the LDPC encoding comprises a first class code rate obtained by taking one block from the first class in B1 at the time, and one block in B2 out of the first k2 blocks, and creating a product block. - View Dependent Claims (8)
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9. A method, comprising:
-
estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission; performing channel estimation to determine channel estimates in reception of the LDPC encoded OFDM signal; and determining an estimated QAM symbols as
-
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10. A method comprising the steps of:
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performing channel estimation to determine channel estimates in a receiver of a fiber optic communication system using LDPC coded OFDM; estimating QAM symbols in a transmitter of the communication system; and obtaining channel information for use in detection and decoding in the communication system, wherein a λ
-configuration, denoted as t-(v,k,{0, 1, . . . , λ
}), is a collection of k-subsets (blocks) of a v-set V such that ever t-subset of V is contained in at most λ
of the blocks and let λ
1- and λ
2-configurations, denoted as t-(v1,k1,{0, 1, . . . , λ
1}) and t-(v2,k2,{0, 1, . . . , λ
2}), be given, denote the number of blocks in λ
1 and λ
2-configurations by b1 and b2, respectively; and
the corresponding set of blocks by B1 and B2, respectively the v1v2-elements in the product configuration are ordered pair of elements (e1,e2), with e1 belonging to B1 and e2 belonging to B2, b=└
b1/k1┘
·
└
b2/k2┘
blocks of a product configuration are obtained as follows, with └
┘
denoted the largest integer less than or equal to the enclosed quantity let the blocks from B1 be grouped into └
b1/k1┘
classes of k1 blocks each the first block in a product configuration is obtained as a k1k2-block of ordered pair of elements ((α
1,β
1), . . . , (α
1,β
k2), . . . , (α
k1,β
1), (α
k1,β
k2)), with α
i (i=1, . . . , k1) belonging to the first block of B1 and Bi (i=1, . . . , k2) belonging to the first block in B2 and the LDPC encoding comprises a first class code rate obtained by taking one block from the first class in B1 at the time and one block in B2 out of the first k2 blocks and creating a product block. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification