Abstract: The present invention provides a versatile system for optimizing data fragmentation in a digital communications—particularly OFDM communications—system. A digital transmission system (100) is provided, having a PHY-level constraint. An array (104, 112) of data transmission parameters (106-110, 114-116), relating to the digital transmission system, is provided. A fragmentation construct (102) is provided, and adapted to determine a number of symbols required to transmit a given data transmission payload. The fragmentation construct calculates (118), based on the number symbols required, and on certain parameter information from the array, a number of bytes of data that must be transmitted in the given data transmission payload in order to minimize pad bits added to the data transmission payload.

Abstract: A method. The method includes producing a first signal match indication based on at least one match indication indicative of a match between at least one signal received in at least one band and a reference signal. The method also includes producing a first signal multipath combined signal based upon the first signal match indication, and detecting a first peak in the first multipath combined signal.

Abstract: The present invention provides a versatile system for selectively spreading carrier data across multiple carrier paths within an Orthogonal Frequency Division Multiplexing (OFDM) system (200), particularly an ultra-wideband (UWB) system. The present invention provides a data input (202), which passes data to a randomizer (204). The data then passes to a convolutional code function (206), the output of which is punctured by puncturing function (208). An interleaver function (210) receives the punctured code data, and cooperatively operates with a mapper element (218) to prepare the coded data for pre-transmission conversion by an IFFT (220). The mapper element (218) comprises a dual carrier modulation function (216), which associates and transforms two punctured code data elements into a format for transmission on two separate signal tones.

Abstract: System for ultra-wideband communications providing high data rates over an extended operating range in the presence of interferers. A preferred embodiment comprises an ultra-wideband (UWB) device that makes use of a portion of the UWB frequency range to help provide good performance in the presence of interferers. Additionally, since only a portion of the UWB frequency range is used, multiple devices can simultaneously transmit and receive by using different portions of the UWB frequency range.

Abstract: A receiver to recover a signal of interest while consuming reduced power in some scenarios. The receiver contains a in-phase channel processing path and a quadrature phase channeling path for down converting an input signal to an intermediate frequency, and then recovering the signal of interest by further processing of the input signal at intermediate frequency. One of the two paths is turned off upon occurrence of a desired condition, which reduces power consumption. In an embodiment, the condition is that the input signal does not contain an image signal of the signal of interest.

Abstract: The present invention provides an enhanced channel estimator for use with an orthogonal frequency division multiplex (OFDM) receiver employing scattered pilot channel estimates. In one embodiment, the enhanced channel estimator includes a time interpolation estimator configured to provide time-interpolation channel estimates having at least one image for a portion of carriers having the scattered pilot channel estimates. The enhanced channel estimator also includes a frequency interpolation estimator coupled to the time interpolation estimator and configured to provide frequency-interpolation channel estimates for each carrier based on image suppression through balanced-error filtering.

Abstract: In at least some embodiments, a method for mitigating interference between an Ultra Wideband (UWB) device and a non-UWB device is provided. The method includes, dynamically determining if a frequency channel associated with the non-UWB device is being used. If the frequency channel is being used, the method adjusts a UWB frequency band used for UWB signal transmission.

Abstract: An efficient bit interleaving scheme for a multi-band OFDM ultra-wideband (UWB) system. The encoded bits of the multi-band OFDM system are interleaved within each OFDM symbol and across OFDM symbols. The bit interleaving scheme minimizes performance degradation due to groups of contiguous OFDM tones experiencing a poor SNR caused by the frequency selective channel, exploits the frequency diversity across sub-bands, randomizes the effect of co-channel interference from simultaneously operating un-coordinated piconets, and randomizes the impact of generic narrow-band interferers present within the UWB spectrum.

Abstract: A wireless device receives an input signal representing a signal of interest (e.g., one or more portions of a packet) on a wireless medium. The input signal may, in addition, contain narrowband interference signals. The wireless device removes the signal of interest from the input signal to produce a residue signal, and analyzes the residue signal to determine the presence of any interference bands in which narrowband interference signals may be present. The wireless device then removes the detected interference bands from the input signal. The residue signal may reveal the presence of interference signals, which might otherwise be hard to distinguish in the input signal. Thus, interference signals with power levels much lower than the power of the signal of interest may be detected and removed.

Abstract: Interleaved analog to digital converter with compensation for parameter mismatch among individual converters. A reference ADC samples an input signal at substantially the same time instances as an individual converter used in the interleaved ADC. The reference values provided by the reference ADC are compared with the digital codes generated by the converter to generate an error value from which estimates of the gain, DC offset and timing errors are computed using statistical techniques. Timing error thus estimated is used to change the phase of the sampling clock provided to the converter, and the gain and DC offset errors estimated are applied to modify the values of reference voltages applied to the converter, thus compensating for parameter mismatches.

Abstract: An efficient bit interleaving scheme for a multi-band OFDM ultra-wideband (UWB) system. The encoded bits of the multi-band OFDM system are interleaved within each OFDM symbol and across OFDM symbols. The bit interleaving scheme minimizes performance degradation due to groups of contiguous OFDM tones experiencing a poor SNR caused by the frequency selective channel, exploits the frequency diversity across sub-bands, randomizes the effect of co-channel interference from simultaneously operating un-coordinated piconets, and randomizes the impact of generic narrow-band interferers present within the UWB spectrum.

Abstract: A method for equalizing data and systems utilizing the method. The method of this invention for equalizing (by shortening the channel response) data includes minimizing a function of the data and a number of equalizer characteristic parameters, where the function utilizes auto-correlation data corresponding to equalized data. Updated equalizer characteristic parameters are then obtained from the minimization and an initial set of equalizer characteristic parameters. Finally, the received data is processed utilizing the equalizer defined by the minimization. The method of this invention can be implemented in an equalizer and the equalizer of this invention may be included in a system for receiving data.

Abstract: A wireless device is provided that distinguishes between multiple piconets. The wireless device includes a preamble component and a correlator component. The preamble component provides a preamble for a wireless fixed frequency interleaving transmission, and the correlator component distinguishes a wireless transmission based on the preamble. A circuit is provided for a wireless receiver to despread a hierarchical sequence made by spreading an M-length sequence with an N-length sequence. The circuit includes a first and second despreaders. The first despreader is coupled to a signal input to despread a received signal. The signal is a fixed frequency interleaved transmission. The second despreader is coupled to an output of the first despreader. The second despreader despreads the output of the first despreader with a second sequence.

Abstract: A wireless device (10, 12) is provided that distinguishes between multiple piconets. The wireless device (10, 12) includes a preamble component (160, 162, 164, 166) and a correlator (150) component. The preamble component (160, 162, 164, 166) provides a preamble (120) for a wireless fixed frequency interleaving transmission, and the correlator component (150) distinguishes a wireless transmission based on the preamble (120). A circuit (180) is provided for a wireless receiver to despread a hierarchical sequence (120) made by spreading an M-length sequence (110) with an N-length sequence (112). The circuit (180) includes a first and second despreaders (185, 190). The first despreader (185) is coupled to a signal input to despread a received signal. The signal is a fixed frequency interleaved transmission. The second despreader (190) is coupled to an output of the first despreader (185). The second despreader (190) despreads the output of the first despreader (185) with a second sequence.

Abstract: A method for equalizing data and systems utilizing the method. The method of this invention for equalizing (by shortening the channel response) data includes minimizing a function of the data and a number of equalizer characteristic parameters, where the function utilizes cyclic differences of equalized data. Updated equalizer characteristic parameters are then obtained from the minimization and an initial set of equalizer characteristic parameters. Finally, the received data is processed utilizing the equalizer defined by the minimization. The method of this invention can be implemented in an equalizer and the equalizer of this invention may be included in a system for receiving data.

Abstract: A system and method implement very high data rate baseband DACs suitable for wireless applications related to new standards (e.g. Ultra-Wide Band) using CMOS processes allowing an integrated solution with the deep-submicron CMOS digital baseband. A single CMOS block working at full speed is discarded in favor of several blocks, each working at a fraction of the original data rate.

Abstract: Communications systems are disclosed which comprise system and methods which, in some embodiments, include a data input; a decoding function, which is adapted to receive a first data element and a second data element from the data input and decode the first data element and second data element, and a mapping element, which is adapted to map the first data element and second data element onto two constellations.

Abstract: The present invention provides an image-rejecting channel estimator for use with an orthogonal frequency division multiplex (OFDM) receiver employing scattered pilot channel estimates. In one embodiment, the image-rejecting channel estimator includes an estimation interpolator configured to provide channel estimates through time interpolation and frequency interpolation employing the scattered pilot channel estimates. The image-rejecting channel estimator also includes an image-rejection formatter coupled to the estimation interpolator and configured to provide image-rejection filtering to suppress an image in an output spectrum of the channel estimates from at least one of the time interpolation and frequency interpolation.

Abstract: Interleaved analog to digital converter with compensation for parameter mismatch among individual converters. A reference ADC samples an input signal at substantially the same time instances as an individual converter used in the interleaved ADC. The reference values provided by the reference ADC are compared with the digital codes generated by the converter to generate an error value from which estimates of the gain, DC offset and timing errors are computed using statistical techniques. Timing error thus estimated is used to change the phase of the sampling clock provided to the converter, and the gain and DC offset errors estimated are applied to modify the values of reference voltages applied to the converter, thus compensating for parameter mismatches.

Abstract: A method of wirelessly communicating is disclosed. The method comprises generating a plurality of tones for a wideband orthogonal frequency division multiplex symbol (310), the tones including a plurality of contiguous zero-valued tones, inverse Fourier transforming the tones to a plurality of time-domain samples (312), copying a plurality of the time-domain samples as a portion of a cyclic block (314), the cyclic block (314) contiguous with the time-domain samples (312), time-domain window filtering the time-domain samples (312) and the cyclic block (314) to form a portion of the wideband orthogonal frequency division multiplex symbol (310), wherein the time-domain window filter (350) is a function ?(k) having the property that ?(k)+?(k+Nfft) is about equal to a constant ? where Nfft is the number of tones, and transmitting the wideband orthogonal frequency division multiplex symbol (310).