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 and apparatus for determining if useful auxiliary information in an auxiliary time slot is available for subscriber unit use. The present invention includes a receiver that receives data from both an auxiliary time slot and a dedicated time slot. Data from the receiver is coupled to a computation function that calculates a metric comparing the data from the auxiliary time slot and the dedicated time slot. The calculated metric is coupled to a threshold comparator that compares the calculated metric to a threshold. Based on the results of the comparison, a determination is made on the presence or absence of useful auxiliary data in an auxiliary time slot.

Abstract: A satellite data receiver, a satellite data receiver controller, a method, an article of manufacture, and a propagated signal, which process polarization information from another satellite data receiver in order to permit multiple types of signals to be received by a conventional outdoor unit of a satellite reception system. The satellite data receiver, satellite data receiver controller, method, article of manufacture, and propagated signal also utilize decoding techniques to ensure no data is lost during a polarization switch. The satellite data receiver, satellite data receiver controller, method, article of manufacture, and propagated signal provide upgraded service without upgrading the outdoor unit and without requiring an installer to enter the consumer's home.

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 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 links of a cellular radio system.

Abstract: A message format and associated method for estimating the frequency and timing offset of a reference burst of a random access channel in a time-division multiple access communications system. A signal structure in which the continuous wave segment is split into two parts separated by some portion of the content of the random access channel burst is used to provide more precise frequency estimation. Iteration of separate frequency and timing estimation procedures is used to refine both estimates, as the individual estimation processes are more accurate when there is less error in the other parameter. Multiple hypothesis testing is used, in which more than one initial frequency estimate is carried through the iteration process, with thresholding to identify the best frequency offset. Reliable rejection of false ambiguities is achieved because the degradation in timing estimation, due to large frequency offsets, can be detected with thresholding.

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 1/2 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 1/2 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 method for improving spectral sampling using Discrete Fourier Transforms in a processor to detect a continuous wave (CW) signal in a burst having large initial uncertainties comprises the steps of dividing the burst into smaller sub-bursts; performing a Discrete Fourier Transform on each sub-burst; and non-coherently combining each sub-burst. A further variation includes selecting an optimal number L of sub-bursts based upon system performance, and desired detection performance at a minimum operating signal to noise ratio.

Abstract: A method of interleaving blocks of indexed data of varying length is disclosed. The method includes the steps of: providing a set of basic Interleavers comprising a family of one or more permutations of the indexed data and having a variable length; selecting one of the basic Interleavers based upon a desired Interleaver length L; and adapting the selected basic Interleaver to produce an Interleaver having the desired Interleaver length L.

Abstract: A method of terminating two or more constituent encoders of a turbo encoder employing a turbo code, comprising the step of: generating tail input bits at each of two or more constituent encoders, including deriving the tail input bits from each of the two or more constituent encoders separately from a contents of shift registers within each of the two or more constituent encoders, after an encoding of information bits by the two or more constituent encoders; puncturing one or more tail output bits such that 1/R output tail bits are transmitted for each of a plurality of trellis branches, wherein R is a turbo code rate employed by the turbo encoder during an information bit transmission. In yet another variation, the step of puncturing the tail output bits further comprises the step of: transmitting, during trellis termination, the tail output bits, only if they are sent from an output branch of one of the two or more constituent encoders that are used during information bit transmission.

Abstract: This disclosure relates to a communication system including a modulator and a demodulator. The 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 burst classifier is useful in a digital communication system transmitting a signal burst of a plurality of different burst types. The burst classifier includes a plurality of filters associated with the plurality of different burst types, respectively. Each filter generates correlation data based on the signal burst and a respective plurality of reference signals offset by a plurality of time offsets. The respective pluralities of reference signals are indicative of a corresponding burst type of the plurality of different burst types. A comparator then analyzes quantities based on the correlation data from each filter to determine the burst type of the signal burst.

Abstract: A method and apparatus for providing auxiliary data in a idle potion of a slot in a time division multiple access system is disclosed. A speech coder converts speech into digital signals that are coupled to a convolutional coder. The convolutional coder processes the digital signals using three or four connection polynomials to create two sets of outputs. One set of outputs, which is generated from first and second connection polynomials is identical to the standard output of a IS-136 convolutional coder. The second set of outputs, which are the auxiliary data, are generated using third and fourth connection polynomials. The second set of outputs is coupled to a puncturing function, which appropriately deletes portions of the second set of outputs. The remaining portion of the second set of outputs is transmitted in the idle portion of a time slot.

Abstract: A method and apparatus for synchronizing and error checking received bitstreams of encoded information is provided. The apparatus includes a single polynomial division shift register. The method involves calculating successive syndromes using the single polynomial division shift register by shifting the received bits of information, generating a syndrome, and comparing the syndrome to a known marker syndrome.