Abstract: A method and apparatus for estimating channel impulse response and data in a signal transmitted over a channel in a communication system. The channel impulse response is estimated uses correlative channel sounding, and then, using the estimated channel impulse response, the data in the signal is estimated. The output is then fed back to the channel impulse response estimator and the channel impulse estimation is repeated. The data estimation and channel impulse response estimation may be iterated a number of times.

Abstract: Method and apparatus for improving the efficiency and the dynamic range of a power amplifier operated with signals having a large peak-to-average ratio. A reference level is determined, above which at least a portion of the magnitude of an input signal being a modulated signal that is input to the power amplifier, or a baseband waveform that is used to generate the modulated signal, is defined as an excess input signal. The magnitude of the input signal is continuously sampled, for detecting an excess input signal. A lower level of operating voltage is supplied to the power amplifier, if no excess input signal is detected. The lower level of operating voltage is sufficient to effectively amplify input signals having a magnitude below the reference level. A higher level of operating voltage is supplied to the power amplifier, whenever an excess input signal is detected. The higher level of operating voltage is sufficient to effectively amplify input signals having a magnitude above the reference level.

Abstract: Method and apparatus for improving the efficiency and the dynamic range of a power amplifier operated with signals having a large peak-to-average ratio. A reference level is determined, above which at least a portion of the magnitude of an input signal being a modulated signal that is input to the power amplifier, or a baseband waveform that is used to generate the modulated signal, is defined as an excess input signal. The magnitude of the input signal is continuously sampled, for detecting an excess input signal. A lower level of operating voltage is supplied to the power amplifier, if no excess input signal is detected. The lower level of operating voltage is sufficient to effectively amplify input signals having a magnitude below the reference level. A higher level of operating voltage is supplied to the power amplifier, whenever an excess input signal is detected. The higher level of operating voltage is sufficient to effectively amplify input signals having a magnitude above the reference level.

Abstract: An apparatus for performance improvement of a digital wireless receiver comprises a processing circuit for processing a plurality of received signals and providing a processed signal, wherein a plurality of weights is applied to the plurality of received signals producing a plurality of weighted received signals. The plurality of weighted received signals are combined to provide the processed signal. A weight generation circuit generates the plurality of weights wherein weights are based on a given number of interferers.

Abstract: A method and apparatus for decoding a frame of multi-rate encoded digital data which contains redundant information provided to validate the decoding operation. A frame of data is received which contains information bits and cyclic redundancy check (CRC) bits. In accordance with the invention, the received frame is decoded and a check is conducted to determine whether the CRC bits correspond correctly for the decoded information bits. If the decoded frame passes the CRC test process, the decoded fame is provided to the user. However, if the decoded frame does not pass the CRC test, then at least one additional decoding process is performed on the received frame. In the first exemplary embodiment of the present invention, on a failure of the CRC check, the data is decoded using a trellis decoder and the data that yields the next most likely path through the trellis is selected.

Abstract: The invention provides methods and apparatus for adaptive adjustment of the phase and amplitude controllers that are needed in Feed Forward Linearized Amplifiers (FFLA) to balance, first, the desired signal component and then the distortion component for the eventual full suppression of the latter. The particular advantage of the methods of the invention is that the adaptive adjustment is achieved without the need for additional RF reference or pilot signals and without RF correlators as proposed in prior art; rather, it is based solely on envelope-detected samples of the signal at two test points and on perturbations of the quiescent operating points of the amplifiers and/or other components, such as vector modulators, by appropriately selected voltage patterns. All these operations are at base band frequencies which makes the apparatus for the adaptive control implementable in simple digital circuitry.

Abstract: An apparatus for performance improvement of a digital wireless receiver comprises a processing circuit for processing a plurality of received signals and providing a processed signal, wherein a plurality of weights is applied to the plurality of received signals producing a plurality of weighted received signals. The plurality of weighted received signals are combined to provide the processed signal. A weight generation circuit generates the plurality of weights, wherein weights are generated so as to solve a minimization problem that penalizes excessive time variability in the weights.

Abstract: A spread spectrum code pulse position modulated communication system is disclosed. The communication system includes a spread spectrum code pulse position modulated receiver that compensates for the delay spread of a transmission medium, such as a wireless radio channel of a local area network. Delay spread may cause signal components of one transmitted spread spectrum codeword to spill over into chip positions of adjacent symbols, causing intersymbol interference, or into chip positions on quadrature channels of a given symbol interval, such as in a QPSK implementation, causing interchip interference. The disclosed receiver decodes a transmitted spread spectrum code pulse position modulated signal in the presence of such delay spread, utilizing a tentative symbol estimator to sample the matched filter data.

Abstract: A spread spectrum code pulse position modulated communication system is disclosed. The frequency spectrum of a transmitted signal is spread by encoding bits with a predefined spectrum-spreading codeword which is in accordance with regulatory requirements or other standardization decisions. When the predefined spread spectrum codeword is passed through a filter matched to the characteristics of the codeword, a peak is detected in the main lobe. A positive main lobe can indicate a binary value of "0" and a negative main lobe, associated with the inverse of the predefined codeword, can represent a binary value of "1". Additional information is conveyed by modulating the position of the center of the codeword within the symbol duration. In one embodiment, the position of the center of the codeword is varied among eight positions. Thus, eight signal states are available, and three additional bits may thereby be conveyed.

Abstract: An improved method and system for performing a pilot signal searching operation in anticipation of handoff in mobile station communication between base stations is disclosed herein. The searching operation is described herein as being implemented within a cellular communication system which uses code division multiple access (CDMA) modulation techniques. The mobile station maintains a list of an Active Set of pilot signals transmitted from base stations with which the mobile station is to communicate through, and a Neighbor Set of pilots from base stations within a predetermined proximity of the mobile station. In addition to the Neighbor and Active Sets of pilots, the mobile station maintains a list of Candidate and Pre-Candidate Sets of pilots. Based on analysis of the signal strength of the pilot signals received at the mobile station, base station entries from the Neighbor Set may be assigned to the Pre-Candidate and Candidate Sets, and eventually to the Active set.

Abstract: In a communication system, a network has nodes each connected in a star relationship to a number of end units that include a device for assuming one of an idle, active, or on-line state and for requesting the node to which it is connected to change it from the idle to the active and the active to the on-line state, and for releasing the on-line state on the basis of data at the end unit. The nodes for change the state of an end unit from the idle to the active and from the active to the on-line mode on the basis of available communication time. According to an embodiment of the invention, the nodes change the states to the on line state on the basis of policy preferences for the type of traffic, and specifically to grant priority to stream traffic over batch traffic.

Abstract: A method and apparatus for producing a frequency-controlled loop in a phase-diversity receiver for demodulating received ON-OFF-keyed (OOK) and phase shift keying (PSK) signals, by feeding a reference frequency signal and the received signals to a quadrature mixer (QM) which produces two output signals in phase quadrature at nominally zero intermediate frequency. Quadrature continuous wave signals void of the modulation are produced from the phase quadrature output signals. A voltage proportional to the frequency of the quadrature continuous wave signals is generated and is utilized for controlling the frequency of the generated reference frequency signal.

Abstract: A method and apparatus are described for demodulating a modulated signal having a carrier component and a data component, in which the modulated signal is split into at least two parts one of which is delayed with respect to the other, and the two parts are multiply-coupled and linearly-combined to produce a combined output corresponding to a function of the data component independent of the carrier component frequency. In the described method and apparatus the undelayed part is coupled with the delayed part in a multiport coupler, wherein the parts are relatively phase-shifted to produce a plurality of phase-shifted signals; and the phase-shifted signals are linearly combined such that the data component, in the function of the combined output, is not affected by variations in frequency or phase of the carrier component. This enables a robust direct-detection DPSK receiver.

Abstract: A method and apparatus for smoothing out phase fluctuations in a monitored input signal by: detecting the partial-cycle differences in phase between the input signal and a reference signal, and generating a first error signal representing the partial-cycle differences in phase; detecting full-cycle differences in phase between the input signal and the reference signal, and generating a second error signal representing the full-cycle differences in phase; and utilizing the first and second error signals for smoothing out the phase fluctuations in the input signal.

Abstract: In the dynamic process for the generation of biased pseudo-random test patterns for the functional verification of integrated circuit designs, the verification is performed in a sequence of steps, with each test pattern providing all data required to test a circuit design during at least one of said steps. Generation of each step is performed in two stages, where in a first stage all facilities and parameters required for the execution of the respective step are defined and assigned the proper values, and where in a second stage the execution of the particular step is performed. This process is continued until a test pattern with the number of steps requested by the user is generated, so that finally the test pattern comprises three parts: The initialized facilities define the initial machine state and execution parts of the test pattern, and the values of the facilities which have been changed during the execution of the steps, form the results part of the test pattern.

Abstract: Ghosts are canceled in received analog TV (for IDTV, EDTV, and HDTV) signals by utilizing the fact that there are short periods of time without the analog signals (the horizontal flyback interval between the lines) to process the received signal on a line-to-line basis using a finite impulse response (FIR) or an infinite impulse response (IIR) equalizer. This line-by-line processing (which can be implemented by periodic cleansing of the equalizer) overcomes the limitations of standard equalizers to allow for 40-50 dB of suppression of ghosts, even with nulls in the spectrum, as long as the ghost delay is less than the period of time without the analog signal. Furthermore, by using time inversion in combination with line-by-line processing, the stability problem of the conventional IIR equalizer is eliminated. The IIR equalizer may be implemented on a single digital integrated circuit. Alternatively, an FIR equalizer can be used which, although it may require multiple chips (i.e.