Abstract: An LDPC based TDS-OFDM receiver for demodulating an LDPC encoded TDS-OFDM modulated RF signal downconverted to an IF signal includes a synchronization block, an equalization block, an OFDM demodulation block and a FEC decoder block. The synchronization block generates a baseband signal from a digitized IF signal and performs correlation of a PN sequence in a signal frame of the received RF signal with a corresponding locally generated PN sequence to provide signals for performing carrier recovery, timing recovery and parameters for channel estimation. The equalization block performs channel estimation and channel equalization. The OFDM demodulation block performs demodulation on the baseband signal to recover OFDM symbols and converts the OFDM symbols to frequency domain. The FEC decoder block includes an LDPC decoder for decoding the OFDM symbols based on the LDPC code to generate a digital output signal indicative of the data content of the RF signal.

Abstract: An LDPC based TDS-OFDM receiver for demodulating an LDPC encoded TDS-OFDM modulated RF signal downconverted to an IF signal includes a synchronization block, an equalization block, an OFDM demodulation block and a FEC decoder block. The synchronization block generates a baseband signal from a digitized IF signal and performs correlation of a PN sequence in a signal frame of the received RF signal with a corresponding locally generated PN sequence to provide signals for performing carrier recovery, timing recovery and parameters for channel estimation. The equalization block performs channel estimation and channel equalization. The OFDM demodulation block performs demodulation on the baseband signal to recover OFDM symbols and converts the OFDM symbols to frequency domain. The FEC decoder block includes an LDPC decoder for decoding the OFDM symbols based on the LDPC code to generate a digital output signal indicative of the data content of the RF signal.

Abstract: Method and system for determining the number of one or more of a sequence of M+1 consecutive OFDM frames from analysis of the designated preambles of two or more consecutive frames (m=0, 1, . . . , M; M?1). An overlap function OF(m;k) is formed for each frame with a sequence of selected reference signals indexed by k (k=1, 2, . . . , K), dependent upon the frame number m and the index k, and a phase (sequence location corresponding to largest amplitude of overlap function) is determined. An Mth-order phase difference is computed that corresponds to frame number of one of the M+1 frames. A consistency check is provided for the phase numbers.

Abstract: A method for constructing a simplified trellis diagram for BCH-encoded information is disclosed. BCH-encoded information is received, having a corresponding parity check matrix H. The parity check matrix H is expressed as an ordered sequence of columns of matrices. A sequence of sub-code words is provided, corresponding to one or more code words, each satisfying a given condition. A matrix Hcp, having columns that are generated as a selected permutation of the columns of the matrix H through a column-permutation-for-binary-matching process, is provided, and a sequence of sub-matrices and a corresponding sequence of permuted sub-code words is provided. A trellis diagram, representing an ordered sequence of code word transitions in the received information and symmetric about a central location, is provided for each code word c, connecting n+1 stages, numbered i=0, 1, . . . , n, in an ordered sequence.

Abstract: Method and system for determining whether one or more multipath signals is present in a received signal frame that includes a reference symbol (RS) sequence RS(t;m1) as part of the frame, and for iteratively evaluating a multipath signal that is present. The RS sequence index (m1) for the frame is identified, and first and second Fourier transforms ?(f;m1;ref) and ?(f;rec) for the received frame are provided for a selected time segment IS that includes the RS sequence of the received frame. An inverse Fourier transform ?(t;m1) of the ratio of the transforms is computed and analyzed. If at least one multipath signal is present, ?(t;m1) is nonlinearly filtered, and the filtered function is convolved with RS(t;m1). This convolution represents a received signal extension, due to multipath signal(s) presence. A refinement procedure analyzes a contribution to multipath signals from the preceding frame(s). The procedure is iteratively driven toward an optimal representation of any multipath signal(s) present.

Abstract: Method and system for adaptively estimating and compensating for phase noise error in a received signal s(t;data). A plurality of transmission parameter symbol (TPS) sets, each with a representative TPS group frequency, are incorporated in the signal before transmission. Received channel response amplitudes are analyzed to select a particular TPS frequency group, and inverse Fourier transforms, N(t) and D(t), are computed for these chosen signals. A complex ratio, r(t)=N(t)/D(t), is computed and used to determine a phase angle ?(t). A phase noise error compensated, time domain signal, equal to exp{?j?(t)}·s(t??t(delay);data) is provided.

Abstract: A method for efficient decoding of block product code format signals, using a (22p)QAM signal constellation for mapping of a received signal, with p=2, 3, 4, 5, . . . A received signal value rx, corresponding to an x=I or x=Q coordinate, is converted to a p-tuple (B(p-1)x, . . . , B0x) corresponding to a “closest” I-coordinate or Q-coordinate numerical value, and a p-stage algorithm is applied to the signal values rx and to the p-tuples (B(p-1)x, . . . , B0x) to determine a p-tuple (r(p-1)x, . . . , r0x) representing a decoded p-bit value for the received signal value rx. Depending upon a communication channel parameter Eb/N0 and the bit error ratio BER associated with each of the p bits, the received signal values rx may be suitable for some or all communications activities (e.g., HDTV, SDTV, mobile comm).