Abstract: A bit loading for a channel of a multi-carrier data communication system is generated. The bit loading has a target bit rate and satisfies predetermined performance criteria. When the channel is loaded according to the bit loading, a minimal number of sub-channels of the channel are active.

Abstract: Orthogonal Frequency Division Multiplexed transmission and reception using a broadcast burst preamble. The preamble comprises at least one first part (A-FIELD) designed for a coarse frame detection and/or an AGC control, and at least one second part (B-FIELD) following the at least one first part in the time domain and being designed for a timing and frequency synchronization. The at least one first part (A-FIELD) and the at least one second part (B-FIELD) each include Inverse Fast Fourier Transformed (IFFT) frequency domain sequences of complex symbols. The frequency domain sequence of the at least one first part (A-FIELD) is set depending on the frequency domain sequence of the at least one second part (B-FIELD) such that a second autocorrelation peak mainly generated by the at least one second part (B-FIELD) of the preamble is optimized. The sequence of complex symbols of the first part differs from the sequence of complex symbols of the second part in at least one symbol.

Abstract: A distortion compensator for compensating for distortion produced in an amplifier that amplifies a signal includes a signal level detector for detecting a level of a signal to be amplified and a distortion compensator for conducting distortion compensation based on the detection result separately for each frequency band signal of multiple frequency band signals contained in the signal to be amplified. The distortion compensator improves distortion compensation performance by reducing the effect of frequency characteristics that restrict the distortion compensation performance limit.

Abstract: A system transmits data on a multi-conductor signal path, which produces a current flow based on the value of the data transmitted. The system reduces changes in current flow between successive data transmissions by encoding data values represented by sets of N bits to produce corresponding sets of M symbols. Each set of M symbols represents multiple bits and each set of M symbols is selected to produce a current flow within a predetermined range of current flows. The sets of M symbols are transmitted across the multi-conductor signal path.

Abstract: In a code division multiple access communication system (100), a method and an accompanying apparatus provide for an efficient control of a gain level of a communication channel at various mobility levels. A rate of change of a carrier to interference ratio (C/I) of a communication channel received at a receiver (400) is determined. The gain level of the communication channel may be based on the rate of change of the C/I of the communication channel. A mobility level of the communication channel may be compared to a low mobility threshold corresponding to a low mobility level. If the mobility level meets the low mobility threshold, the gain level of the communication channel may be based on the rate of change of the C/I of the communication channel.

Abstract: A receiver circuit for a communications terminal includes a signal pre-processing circuit having: an analog/digital converter device with K analog/digital converters connected in parallel, a conversion device, and a filter device connected downstream of the conversion device. The filter device has N digital filters connected in parallel, where N is an integer that is greater than or equal to 1 and is less than K.

Abstract: In a cable television (CATV) data communication network, channel throughput and communications robustness are increased in a manner that improves speed of data transmission while maintaining compatibility with existing specifications and equipment. Enhanced throughput can be realized using the return channel of the CATV network. Alternatively, data retransmission and/or diversity techniques can be used to improve throughput.

Abstract: A method and apparatus for determining an optimum modulation scheme for a retransmission in a communication system supporting HARQ. When two modulation schemes are available, at an initial transmission, information is modulated in the lower-order modulation scheme if a first MPR is less than a first threshold, and in the higher-order modulation scheme if the first MPR is greater than or equal to the first threshold. Here, an MPR is determined by an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for a transmission. To select one of the modulation schemes for a retransmission, a second MPR is calculated using an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for the retransmission. If the first MPR is equal to or less than a second threshold greater than the first threshold, the lower-order modulation scheme is selected.

Abstract: A time history display of orthogonal code power levels by spreading factor is generated by displaying each data record of code domain power as a line, with each point in the line representing a different code index and the color or brightness of each data point representing the associated base code power level. With the data records displayed as contiguous lines, as each new data record is acquired it is added as a new line of the display while the line representing the oldest data record is deleted from the display. For communications standards where the code spreading factor varies, both bit-reversed and Walsh code graphs are displayed to show the grouping of the sub-codes that make up a base code. In this way the time history display indicates timing and trend information to a user.

Abstract: A data compression method and system replaces pairs of symbols in a string of symbols by a single new symbol. A method for selecting the pairs of symbols to be replaced employs a modified greedy algorithm. The method selects a next best pair of symbols for replacement by considering pairs that have a potential for usurping a current best candidate pair of symbols, due to their frequency of occurrence. A minimum savings threshold is evaluated to further avoid exhaustive searches of all possible pairs of symbols.

Abstract: A clipped metric function is utilized to mitigate the adverse effects of impulsive noise (e.g., lightening, motor vehicle ignition noise) on communications signals. The clipped metric function may be used alone or in conjunction with conventional signal clipping. In one embodiment, a clipped Euclidean metric function is determined as a function of the input signal. The input signal is processed in accordance with the clipped Euclidean metric function, to provide a clipped metric signal. The clipped metric signal is processed in accordance with application dependent requirements. The clipped metric function provides improved performance over conventional signal clipping. For example, utilization of a clipped metric function provides improved performance in situations in which the impulsive noise does not increase the amplitude of the input signal to a level that would be clipped by signal clipping.

Abstract: The present invention is related to a method and system for optimization of channel estimation and synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) Multiple-Input Multiple-Output (MIMO) wireless communication system. In accordance with the present invention, all of the training sequences are simply constructed based on a basic code by cyclically shifting the basic code. The training sequences are transmitted from different antennas in parallel without performing inverse fast Fourier transform. As a result, there is no peak-to-average ratio problem. Channel estimation is performed in each receiver based on the samples before fast Fourier transform and the maximum-likelihood estimate of channel response in time domain is then mapped into the frequency domain. The channel estimation is not only very simple in implementation, but also very efficient in computation.

Abstract: Described is a transmission system for transmitting a multicarrier signal from a transmitter (10) to a receiver (20). The receiver (20) comprises an equalizer (24) for canceling intercarrier interference which may be included in the received multicarrier signal. The equalizer (24), which preferably is a MMSE equalizer, comprises a reduced complexity filter for deriving a vector of estimated symbols (25) from a vector of received symbols (23). The reduced complexity filter comprises a multiplication of an approximation of an inverse matrix R?1 with the vector of received symbols (23). The approximation of the inverse matrix R?1 is preferably a first order approximation.

Abstract: A signal encoding apparatus encodes one-bit signals of a plurality of n channels in a delta-sigma manner. The apparatus includes a phase modulator for phase-modulating the one-bit signals as original signals to add data of inverted phases to the one-bit signals. Information data related to the one-bit signals are added to the phase-modulated one-bit signal by rearranging the data of inverted phases based on a plurality of m channel units of the n channels, where n?m?2 and by exclusive ORing the information data and the phase-modulated one-bit signal data.

Abstract: A clock phase control circuit is provided for controlling the clock phase of a transceiver, having a sampling circuit for sampling an analog received signal with a sampling clock signal; an echo signal compensation circuit for compensating an echo signal which is produced by means of a transmit signal transmitted by the transceiver, it being possible to set the echo signal compensation circuit in an adaptive fashion as a function of a setting signal; a control circuit for generating a control signal for controlling the clock phase, which control signal specifies the phase deviation between the signal phase of the sampling clock signal and a setpoint signal phase of an ideal sampling clock signal; a loop filter for filtering the control signal; a phase counter for generating the sampling clock signal as a function of the filtered control signal described [sic].

Abstract: A transmitter for a digital transmission signal includes a pre-distorter to improve linearity of a power amplifier. An amplified transmission signal is conditioned into a narrowband feedback signal that is responsive to a logarithm of the power appearing in out-of-band components of the amplified transmission signal. The feedback signal is processed in a pre-distortion processor that implements a genetic algorithm to adapt pre-distortion functions implemented in the pre-distorter and improve linearity over time. The genetic algorithm tests a population of randomly-generated pre-distortion functions for fitness. A baseline component of the coefficients from pre-distortion functions used in a subsequent population tracks the best-fit pre-distortion function from the current population, allowing the use of a limited search space. New populations are generated from old populations using an elitism process, and randomized crossover, and mutation processes.

Abstract: In a first microcomputer, a communication function is provided for outputting a data signal having a transmission period Tr that has a relation of Td<Tp/2 with a data time Td, and it sends various data processed by itself and carried on the data signal to a second microcomputer, where the received data signal is sequentially stored in a memory, and the various data are read by timing pulses for reading and processed.

Abstract: The invention provides methods and apparatus for multiple user detection (MUD) processing that have application, for example, in improving the capacity CDMA and other wireless base stations. One aspect of the invention provides a multiprocessor, multiuser detection system for detecting user transmitted symbols in CDMA short-code spectrum waveforms. A first processing element generates a matrix (hereinafter, “gamma matrix”) that represents a correlation between a short-code associated with one user and those associated with one or more other users. A set of second processing elements generates, e.g., from the gamma matrix, a matrix (hereinafter, “R-matrix”) that represents cross-correlations among user waveforms based on their amplitudes and time lags. A third procesing element produces estimates of the user transmitted symbols as a function of the R-matrix.

Abstract: The invention provides methods and apparatus for multiple user detection (MUD) processing that have application, for example, in improving the capacity CDMA and other wireless base stations. One aspect of the invention provides a multiprocessor, multiuser detection system for detecting user transmitted symbols in CDMA short-code spectrum waveforms. A first processing element generates a matrix (hereinafter, “gamma matrix”) that represents a correlation between a short-code associated with one user and those associated with one or more other users. A set of second processing elements generates, e.g., from the gamma matrix, a matrix (hereinafter, “R-matrix”) that represents cross-correlations among user waveforms based on their amplitudes and time lags. A third procesing element produces estimates of the user transmitted symbols as a function of the R-matrix.

Abstract: This disclosure is directed toward a wireless device configured to support a plurality of wireless protocols. More specifically, the wireless device includes signal processing components that can be used in more than one communication mode. Accordingly, distinct components conventionally used in a wireless device that supports a plurality of protocols may be eliminated in favor of one or more common components that can be used in the different communication modes. In one example, an analog filter is used to filter baseband signals associated with a first protocol and a second protocol. A digital filter can then be used to perform additional filtering on digital baseband signals associated with the second protocol. By using a common analog filter for analog filtering of baseband signals associated with different protocols, the architecture and design of a wireless device can be simplified.