Systems and methods for advanced iterative decoding and channel estimation of concatenated coding systems
First Claim
1. A method for iteratively decoding a hybrid digital radio signal, the signal being an Orthogonal Frequency-Division Multiplexed (OFDM) signal comprising OFDM reference subcarriers, OFDM data subcarriers, and OFDM symbol intervals, the method comprising:
- a. performing, by a demodulator and by a de-mapper, OFDM demodulation and subcarrier de-mapping of the hybrid digital radio signal into system control and data sequences symbols to obtain, by a control data decoder, received distorted modulated symbols;
b. performing, by a channel estimator, initial channel state information estimation based on the received distorted modulated symbols, from the control data decoder, wherein said received distorted modulated symbols are carried by a plurality of OFDM data subcarriers and a plurality of OFDM reference subcarriers in at least one OFDM symbol interval;
c. performing, by the channel estimator, phase correction of the received distorted modulated symbols based on the initial channel state information estimation into coherent demodulated signals;
d. performing, by a symbol-to-bit demapper, symbol-to-bit demapping of the coherent demodulated signals by calculating log-likelihood ratios of the system control and data sequences symbols;
e. producing, by a de-interleaver and demultiplexer, one or more logical channel signals by de-interleaving and demultiplexing the log-likelihood ratios of the system control and data sequences symbols;
f. processing the one or more logical channel signals by producing, by a decoder, soft estimates of convolutional code coded bits using soft-input soft-output decoding of one or more convolutional codes associated with the one or more logical channels, wherein the soft-input soft-output decoding of the one or more convolutional codes comprises depuncturing one or more convolutional coded bit sequences;
g. calculating, by the channel estimator, improved channel state information by performing at least one additional iteration of channel state information estimation based on at least some of said soft convolutional code coded bits estimates; and
h. performing, by a convolutional decoder, enhanced convolutional decoding of at least one of a Program Service Data (PSD) Protocol Data Unit (PDU), a Primary In-Band On-Channel Data Service (PIDS) PDU, audio packet data, a Main Program Service (MPS) PDU header and an Advanced Application Service (AAS) PDU using said improved channel state information.
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Abstract
Systems and methods for decoding block and concatenated codes are provided. These include advanced iterative decoding techniques based on belief propagation algorithms, with particular advantages when applied to codes having higher density parity check matrices. Improvements are also provided for performing channel state information estimation including the use of optimum filter lengths based on channel selectivity and adaptive decision-directed channel estimation. These improvements enhance the performance of various communication systems and consumer electronics. Particular improvements are also provided for decoding HD Radio signals, including enhanced decoding of reference subcarriers based on soft-diversity combining, joint enhanced channel state information estimation, as well as iterative soft-input soft-output and list decoding of convolutional codes and Reed-Solomon codes. These and other improvements enhance the decoding of different logical channels in HD Radio systems.
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Citations
28 Claims
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1. A method for iteratively decoding a hybrid digital radio signal, the signal being an Orthogonal Frequency-Division Multiplexed (OFDM) signal comprising OFDM reference subcarriers, OFDM data subcarriers, and OFDM symbol intervals, the method comprising:
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a. performing, by a demodulator and by a de-mapper, OFDM demodulation and subcarrier de-mapping of the hybrid digital radio signal into system control and data sequences symbols to obtain, by a control data decoder, received distorted modulated symbols; b. performing, by a channel estimator, initial channel state information estimation based on the received distorted modulated symbols, from the control data decoder, wherein said received distorted modulated symbols are carried by a plurality of OFDM data subcarriers and a plurality of OFDM reference subcarriers in at least one OFDM symbol interval; c. performing, by the channel estimator, phase correction of the received distorted modulated symbols based on the initial channel state information estimation into coherent demodulated signals; d. performing, by a symbol-to-bit demapper, symbol-to-bit demapping of the coherent demodulated signals by calculating log-likelihood ratios of the system control and data sequences symbols; e. producing, by a de-interleaver and demultiplexer, one or more logical channel signals by de-interleaving and demultiplexing the log-likelihood ratios of the system control and data sequences symbols; f. processing the one or more logical channel signals by producing, by a decoder, soft estimates of convolutional code coded bits using soft-input soft-output decoding of one or more convolutional codes associated with the one or more logical channels, wherein the soft-input soft-output decoding of the one or more convolutional codes comprises depuncturing one or more convolutional coded bit sequences; g. calculating, by the channel estimator, improved channel state information by performing at least one additional iteration of channel state information estimation based on at least some of said soft convolutional code coded bits estimates; and h. performing, by a convolutional decoder, enhanced convolutional decoding of at least one of a Program Service Data (PSD) Protocol Data Unit (PDU), a Primary In-Band On-Channel Data Service (PIDS) PDU, audio packet data, a Main Program Service (MPS) PDU header and an Advanced Application Service (AAS) PDU using said improved channel state information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification