Abstract: There is provided an information processing apparatus including an encoding unit that represents input data containing mutually different first and second bit values by a plurality of first amplitude values for the first bit value and a second amplitude value that is different from the first amplitude values for the second bit value, does not take an identical value consecutively, and perform encoding so that polarity of the amplitude value is reversed for each cycle, and a transmission unit that transmits a signal encoded by the encoding unit through a predetermined transmission line.

Abstract: A computer system with a phase detector that generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The delay value of a voltage-controlled delay circuit and the phase relationship between the first and second clock signals to a predetermined phase relationship are thereby adjusted.

Abstract: A method, radio receiver, and system to autonomously receive and decode a plurality of signals having a variety of signal types without a priori knowledge of the defining characteristics of the signals is disclosed. The radio receiver is capable of receiving a signal of an unknown signal type and, by estimating one or more defining characteristics of the signal, determine the type of signal. The estimated defining characteristic(s) is/are utilized to enable the receiver to determine other defining characteristics. This in turn, enables the receiver, through multiple iterations, to make a maximum-likelihood (ML) estimate for each of the defining characteristics. After the type of signal is determined by its defining characteristics, the receiver selects an appropriate decoder from a plurality of decoders to decode the signal.

Abstract: A system and method that demodulates the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

Abstract: A method for transmitting feedback information via a Spatial Rank Index (SRI) channel includes determining, at an access terminal, a value of a spatial rank index and transmitting, from the access terminal through the SRI channel, feedback information indicating the determined value of the spatial rank index according to a prescribed coding. The codeword of the prescribed coding is one of: (0,0,0,0,0,0,0,0), (1,0,1,0,1,1,0,1), (0,1,1,1,0,0,1,1), or (1,1,0,1,1,1,1,0).

Abstract: A method of processing broadcast data in a broadcast transmitting system includes Reed-Solomon (RS) encoding and cyclic redundancy check (CRC) encoding enhanced data bytes; converting the RS-CRC encoded enhanced data bytes into enhanced data bits; encoding each of the converted enhanced data bits with one of a first coding rate and a second coding rate, thereby outputting data symbols; first interleaving the data symbols; converting the first interleaved data symbols into data bytes; forming a first data group including enhanced data corresponding to the converted data bytes; deinterleaving data of the first data group; outputting enhanced data packets including the deinterleaved data of the first data group; multiplexing the enhanced data packets with main data packets including main data; second interleaving data of the multiplexed data packets; and trellis encoding the second interleaved data.

Abstract: A digital television (DTV) transmitting system is provided that includes an encoder, a group formatter, a packet formatter and a transmission unit. The group formatter forms data groups where the plurality of second known data sequences are spaced 16 segments apart within at least one of the data groups that includes a transmission parameter inserted between the first known data sequence and the plurality of second known data sequences and the first known data sequence has a first M-symbol sequence and a second M-symbol sequence, the first M-symbol sequence and the second M-symbol sequence have a first pattern, each of the plurality of second known data sequences has a second pattern other than the first pattern, and the second pattern is positioned from a last symbol to a previous N symbol in each of the plurality of second known data sequences.

Abstract: Methods and systems are provided for searching for a codeword from a plurality of codewords in a codebook for use in precoding, for example, as used in a multiple-input multiple-output (MIMO) transmission system. Tree search and recursive algorithm techniques may be utilized to reduce the complexity and enhance the efficiency of the codebook search. Distance values may be determined between an optimal codeword and codewords in a codebook. The distance values may be accumulated for a group of the k-best codewords. Additionally or alternatively, a codeword from the codebook may be removed from consideration if the codeword meets a stop rule condition. A codeword may be selected from the codebook based on a minimum distance value from the optimal codeword.

Abstract: Apparatus and methods for removing dc offsets in feedback loops such as may be used in communication circuits are disclosed. A comparator may be used to sample the output of the feedback loop, with the comparator output applied to a DSP module. The DSP module is configured to determine a dc offset in the output signal and generate an offset correction signal, which may then be applied to the input of the feedback loop to adjust the de offset.

Abstract: Techniques for producing an output signal using an outphasing transmitter are disclosed. In some examples, constant modulation (CM) signals may be produced from a digital input signal. The CM signals may be converted to an analog state and filtered. The signals may then be modulated to produce modulated signals, which may be amplified. The amplified signals may be combined to produce combined signals, which may further be combined to produce an output signal.

Abstract: A MIMO-OFDM transmission and reception apparatus is provided which allows high accuracy estimation of frequency offset, high accuracy estimation of a transmission path fluctuation and high accuracy synchronization/signal detection. A mapping section generates a plurality of OFDM signals. In these OFDM signals, some pilot carriers are assigned to the same carrier position and orthogonal sequences are assigned to the same time slot in the same carrier position.

Abstract: A code phase signalling module arranged to provide code phase signalling to assist in signal acquisition of direct sequence spread spectrum signalling received by a receiver module from a transmitter module. The code phase signalling is arranged to be used by the receiver module to synchronise the phase of a synchronisation code provided from within the receiver module with the phase of a modulation code of the direct spread spectrum sequence signalling received by the receiver module. The synchronisation code sequence corresponds to the modulation code sequence. The code phase signaling module is arranged to provide code phase time signaling representing the offset time of the synchronisation code from a reference time. The reference time is associated with the time of transmission of a particular reference portion of the modulation code of the direct spread spectrum signaling.

Abstract: A system is disclosed for operating a plurality of receiver paths and/or a plurality of transmitter paths in a single mode or multiple mode configuration.

Abstract: A multipath detector includes an RF module receiving multiple signals, and a correlator module receiving the signals from the RF module. The correlator module correlates the signals to create a composite ACF, and produces samples of the composite autocorrelation function (ACF). The samples are time delayed relative to each other. The multipath detector also includes a carrier phase processor that receives the samples and estimates carrier phases associated with each of the samples. The carrier phase processor employs the estimated carrier phases to determine if one of the signals is subject to a multipath delay.

Abstract: A system includes an encoding module, a symbol selection module, a subcarrier selection module, and a mapping module. The encoding module receives symbols for transmission over K subcarriers and T antennas, encodes the symbols using a space time code, and generates space time coded (STC) versions of the symbols, where K and T are integers greater than 1. The symbol selection module selects T adjacent ones of the symbols and selects STC versions of the T adjacent ones of the symbols. The subcarrier selection module selects one of the K subcarriers for transmitting the T adjacent ones of the symbols and the STC versions of the T adjacent ones of the symbols. The mapping module maps the T adjacent ones of the symbols onto the T antennas for transmission over the selected one of the K subcarriers, respectively, and maps the STC versions of the T adjacent ones of the symbols onto the T antennas for transmission over the selected one of the K subcarriers.

Abstract: An apparatus for recovering data and a method thereof are provided. The apparatus includes a reference clock generator which generates a reference clock, and a data recovering unit which detects an edge of received data and recovers the data using a time difference between a reference point of the reference clock and the detected edge.

Abstract: Systems and methods for reducing the peak-to-average ratio (PAR) at the transmitter can reduce the dynamic range required in various analog components. PAR can be reduced by applying a time-domain compensation signal which reduces the magnitude of peaks in the time-domain signal prior to transmission where the time-domain compensation signals use tones that are reserved for the purpose of reducing the PAR. The reservation of these reserved tones for PAR can be implemented by altering the typical startup procedures in a digital subscriber line (xDSL) system. The use of the reserved tones to reduce the PAR can be implemented using a low complexity algorithm or using an adaptive technique.

Abstract: A transmitter for transmitting data in a communication system includes: a serial/parallel (S/P) conversion unit configured to convert data into an I signal and a Q signal; multiplication units configured to multiply the converted I and Q signals by orthogonal sequences, respectively; conversion units configured to Hilbert-transform the I and Q signals multiplied by the orthogonal sequences; addition units configured to add the I and Q signals multiplied by the orthogonal sequences and the Hilbert-transformed Q and I signal, respectively; and an intermediate frequency (IF)/radio frequency (RF) unit configured to up-convert the added I signal and the added Q signal and transmit the converted I and Q signals.

Abstract: Methods and apparatus are provided for computing reliability values in a pipeline. A reliability value portion is computed, with control circuitry in a first pipeline stage, based on a difference between a received input signal value and an expected value. The reliability value portion is combined, in a second pipeline stage that follows the first pipeline stage, with a first value derived from the received input signal to generate a first reliability value. A determination is made as to whether to update the first reliability value in a third pipeline stage based on a combination of the first reliability value with a second reliability value that corresponds to a second value derived from the received input signal.

Abstract: The present invention includes a time-division-multiple-access (TDMA) communication system having a base station and at least one mobile station, each transmitting and receiving an analog radio-frequency signal carrying digitally coded speech. The speech is encoded using a vocoder which samples a voice signal at variable encoding rates. During periods when the radio-frequency channel is experiencing high levels of channel interference, the encoded voice channel having a lower encoding rate is chosen. This low-rate encoded voice is combined with the high degree of channel coding necessary to ensure reliable transmission. When the radio-frequency channel is experiencing low levels of channel interference, less channel coding is necessary and the vocoder having a higher encoding rate is used. The high-rate encoded voice is combined with the lower degree of channel coding necessary to ensure reliable transmission.