Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: A method and apparatus for interleaving an input data stream for parsed parallel concatenated code encoding, the method comprising the steps of: parsing the input data stream into a plurality of parsed data substreams; and forming sets of shared information bits, wherein each of the sets of shared information bits comprises information bits in common with respective pairs of the plurality of parsed data substreams. In a variation, a further step comprises constructing constituent permutations of one or more of the sets of shared information bits. In yet a further variation, a further step comprises interlacing respective pairs of the sets of shared information bits to form respective interleaved data substreams.

Abstract: General binary design criteria for PSK-modulated space-time codes are provided. For linear binary PSK (BPSK) codes and quadrature PSK (QPSK) codes, the rank (i.e., binary projections) of the unmodulated code words, as binary matrices over the binary field, is used as a design criterion. Fundamental code constructions for both quasi-static and time-varying channels are provided.

Abstract: An encoder, decoder, method of encoding, and method of decoding which preserves the turbo coder performance in the waterfall region, while improving upon performance in the error asymptote region, by applying a parser or other similar element to the input bit stream. The parser assigns input bits to a subset of constituent encoders in a pseudo-random fashion. The parsing strategy breaks up input sequences producing low Hamming weight error events, thereby improving the weight spectrum and asymptotic performance of the code, while not impacting waterfall region performance. The parser or other similar element may also strengthen the weight spectrum without adversely affecting convergence of a corresponding decoder.

Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: Space-time codes for use with layered architectures with arbitrary numbers of antennas are provided such as rate k/n convolutional codes (e.g., rates higher than or equal to 1/n where n is the number of transmit antennas). Convolutional codes for layered space-time architectures are generated using matrices over the ring F[[D]] of formal power series in variable D.

Abstract: A modulator produces a modulated signal including a carrier and data signals representing data bits. The data signals include at least two in-phase modulating pulses which have different shapes and which are interfering in time and frequency; the data signals further include at least two quadrature modulating pulses which have different shapes and which are interfering in time and frequency. The modulator includes a filter for producing each shape of pulse, and combining circuits for combining the pulses with each other and with a carrier. The demodulator (or receiver) receives the combined signal and separates the pulses from the carrier. The demodulator further includes filters for separating the pulses, and a circuit for processing the pulses to reproduce the data bits. The processing circuit preferably includes one or more maximum likelihood sequence estimation equalizers.

Abstract: A system and method employing a rate matching algorithm for providing an optimized pattern for puncturing parity bits of a turbo encoded data word of a given rate to produce a turbo encoded data word of a desired lower rate, to thus eliminate bits from said turbo encoded data word to be transmitted by a transmitter. The system and method determine a final amount of bits to be transmitted in the encoded data word, and determine, based on the final amount of bits in relation to the original number of bits in the encoded data word, the number of parity bits to be eliminated from transmission in the encoded data word. Because the parity bits typically have been inserted into the encoded data word by different encoders, the system and method uses a rate matching algorithm to provide an optimized pattern for puncturing the parity bits so that substantially the same number of parity bits provided by each encoder are punctured.

Abstract: A system and method for establishing an integrated forward error correction (FEC) scheme to perform multi-rate encoding on different priority data bits of a channel access message transmitted on a random access channel between devices of a communications network, such as between an access terminal and a base station of a satellite-based communications network. The channel access message includes a first data group representing first information and a second data group representing second information, which is transmitted between an access terminal and a base station in a satellite-based communications network. The system and method encodes the second data group at an encoding rate to provide a second encoded data group, and encodes the first data group at the same encoding rate to provide a first encoded data group. The encoding of the first and second data groups is performed by a single encoder, such as a rate ¼ convolutional encoder.

Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: Space-time codes for use with layered architectures with arbitrary numbers of antennas are provided such as rate k/n convolutional codes (e.g., rates higher than or equal to 1/n where n is the number of transmit antennas). Convolutional codes for layered space-time architectures are generated using matrices over the ring F[[D]] of formal power series in variable D.

Abstract: An approach for performing computations that require processing of values in a forward sweep as well as a reverse sweep, such as the Maximum A Posteriori (MAP) algorithm, is disclosed. A first series of values are computed, in which only every fth value of the first series of values and associated normalization values are stored. The first series of values are indexed such that these first series of values are partitioned in time as blocks. The first series of values are recalculated on a per block basis, whereby a second series of values are calculated in response to these recalculated first series of values.

Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: A method of providing forward error correction for data services uses a parallel concatenated convolutional code which is a Turbo Code comprising a plurality of eight-state constituent encoders wherein a plurality of data block sizes are used in conjunction with said Turbo Code. A variation uses the method in a cellular radio system. Another variation uses the method in both forward and reverse likes of a cellular radio system.

Abstract: A system and method for establishing an integrated forward error correction (FEC) scheme to perform multi-rate encoding on different priority data bits of a channel access message transmitted on a random access channel between devices of a communications network, such as between an access terminal and a base station of a satellite-based communications network. The channel access message includes a first data group representing first information and a second data group representing second information, which is transmitted between an access terminal and a base station in a satellite-based communications network. The system and method encodes the second data group at an encoding rate to provide a second encoded data group, and encodes the first data group at the same encoding rate to provide a first encoded data group. The encoding of the first and second data groups is performed by a single encoder, such as a rate ¼ convolutional encoder.

Abstract: A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

Abstract: A method and apparatus for Turbo encoding uses a set of rate-compatible Turbo Codes optimized at high code rates and derived from a universal constituent code. The Turbo Codes have rate-compatible puncturing patterns. The method comprises: encoding a signal at a first and second encoder using a best rate ½ constituent code universal with higher code rates, the first encoder and the second encoder each producing a respective plurality of parity bits for each information bit; puncturing the respective plurality of parity bits at each encoder with a higher rate best puncturing patterns; and puncturing the respective plurality of parity bits at each encoder with a lower rate best puncturing pattern. In a variation, the best rate ½ constituent code represents a concatenation of polynomials 1+D2+D3 (octal 13) and 1+D+D3 (octal 15), D a data bit. A Turbo Encoder is provided which has hardware to implement the method.

Abstract: A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that is configured to output a plurality of input signals. The transmitter also includes an encoder that is configured to generate a plurality of output signals in response to the plurality of the input signals to output a code word according to the plurality of output signals, wherein the code word has a predetermined algebraic construction for space-frequency coding based upon the communication channel being characterized as a frequency selective block fading channel. Further, the transmitter includes a modulator that is configured to modulate the code word for transmission over the communication channel, and a plurality of transmit antennas that configured to transmit the modulated code word over the communication channel.

Abstract: A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that is configured to output a message signal, and an encoder that is configured to generate a code word in response to the message signal. The code word is based upon a stacking construction that is generalized for the communication channel. The communication channel is characterized as a multi-input multi-output (MIMO) block fading channel. The transmitter also includes a modulator that is configured to modulate the code word for transmission over the communication channel. Further, the transmitter includes a plurality of transmit antennas that are configured to transmit the modulated code word over the communication channel. The system also includes a receiver, which has a plurality of receive antennas. The receiver is configured to receive the transmitted code word via the plurality of receive antennas.

Abstract: A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that outputs a message signal. The transmitter also includes an encoder that generates a code word in response to the message signal. The code word has a construction that defines a plurality of paths associated with an intersymbol interference (ISI) environment of the communication channel, wherein the code word achieves a diversity based upon the number of transmit antennas and the number of ISI paths. Further, the transmitter includes a modulator that modulates the code word for transmission over the communication channel, and multiple antennas that transmit the modulated code word over the communication channel. The system encompasses a receiver that receives the transmitted code word via a number of receive antennas.