Abstract: Over a channel, a signal including a desired portion associated with a desired channel and an undesired portion mixed with said desired portion may be received. Based on prior knowledge and/or empirical estimation of the desired channel and an empirical estimate of the signal cross-covariance, the desired portion from the received signal may be recovered by adaptively equalizing the channel. In one embodiment, a receiver, such as a mobile device (e.g., a cellular phone) includes a processor operably coupled to a communication interface including at least two antennas to receive the signal. The receiver may further include a MODEM that may be operably coupled to the processor, that includes an adaptive equalizer capable of detecting the signal in the presence of co-channel interference from several independent sources, inter-symbol interference and fading, for recovering the desired portion in a cellular environment with time division multiple access (TDMA) to enable digital transmission of the signal.

Abstract: A multi-user detector for use in a CDMA receiver system includes a channel tap interpolator to generate interpolated channel taps for users of interest. The interpolated channel taps occur at integer multiples of a chip period from a sampling reference point. The channel tap interpolation allows detection processing to proceed in the chip domain, rather than in the sample domain, thus reducing the complexity of the multi-user solution significantly. In at least one approach, a number of low dimensionality “virtual” users are defined based on the recursive property of the spreading sequences. Solutions may then be developed for the virtual users using conventional detection (e.g., MMSE) techniques.

Abstract: A communication device including a per finger interference reducer adapted to remove an interference effect of at least one pilot signal from the output of a despreader of the finger.

Abstract: A receiver in a wireless communication system utilizes a metric to minimize the error probability in transmitted information. The receiver may use a detector utilizing multiuser detection or rake detection. The output symbols of the detector are examined and a metric is obtained related to the noise and interference that may have distorted the transmission of the symbol. This metric is supplied to a channel decoder along with the symbol to improve decoding.

Abstract: In an embodiment, a transmitter section for a mobile device includes a predistorter for predistorting an input signal input to a modulation section. Predistortion values may be selected from a look-up table in response to a fed back signal from the output of the modulation section. A delay between the input signal and the fed back signal may be determined in two stages: a coarse delay estimation for determining a whole number of sample cycles, and a fine delay estimation for determining a fraction of a sample cycle to be added to the coarse delay estimation value.

Abstract: Interference reduction is achieved within a communication device using a low complexity antenna array. In at least one embodiment, phase and magnitude values associated with an antenna element within a low complexity array are dynamically adjusted during device operation in a manner that enhances a predetermined quality criterion (e.g., SINR).

Abstract: The cross-correlation between spreading sequences in a CDMA cellular telephone may be determined by generating a pilot code and a channel code. The pilot and channel code are passed to an exclusive OR gate that indicates to a binary counter the number of times that the codes are the same or different. This information may then be utilized to determine the cross-correlation values.

Abstract: In a receiver receiving a signal, the signal including data which is at least modulated by a cyclic sequence, a method for operating the receiver, the method including the steps of receiving a portion of the signal, the portion being modulated by a predetermined section of the cyclic sequence, receiving an additional portion of the signal, the additional portion being modulated by the predetermined section of the cyclic sequence, jointly processing the portion and the additional portion and producing a set of receiver parameters, the receiver parameters minimizing a predetermined cost function for the predetermined section of the cyclic sequence.

Abstract: Estimates of interference from co-channel pilot signals from one or more base stations may be formed at a receiver and subtracted out from the received signal to improve the detection of a desired signal. The complexity of pilot interference cancellation may be reduced by selecting only particular crosscorrelation terms to be estimated and processed. The remaining terms or crosscorrelation values may be eliminated from the computation, reducing computational complexity. In addition, selection decisions may be stored to reduce the need to excessively reevaluate the selection decision.

Abstract: A packet of encoded data is received and decoded using a look-up table that stores information approximating output of an algorithmic decoding process.

Abstract: A switchable low pass filter includes a first switch connected to a first resistive element, a second switch connected to a second resistive element, and a capacitive element connected to the first and second resistive elements. The switchable low pass filter also includes a controller connected to the first switch and the second switch, the controller operative to open and close at least one of the first switch and the second switch. A method for producing a pulse density modulated signal whose pulse timing is jittered includes the following steps; adding a substantially random number and a multi-bit number to a value stored in a flip flop, thereby producing a sum; if the sum is less than an upper limit, storing the sum in the flip flop, thereby replacing the value; if the sum is not less than the upper limit, producing a pulse, subtracting the upper limit from the sum, thereby producing a result, and storing the result in a flip flop; and repeating the steps.

Abstract: Apparatus and a method for receiving spread-spectrum signals is provided. The method includes the steps of detecting a noisy user signal from a spread-spectrum signal including at least a first user signal (including data therein) and at least one pilot signal, and removing an interference effect of the pilot signal on the first user signal from the noisy user signal thereby to create a noise reduced user signal.

Abstract: In a receiver having at least two fingers, the fingers tracking at least one path of a multipath channel, a method includes the steps of forming a finger block of at least two of the two fingers and jointly tracking the fingers of said finger block. The step of jointly tracking includes the steps of generating direction metrics of each of a set of possible directions of joint movement of the fingers of the finger block, selecting one of the direction metrics according to a predetermined criterion, and moving the fingers of the finger block in the directions indicated by the selected direction metric.

Abstract: In a receiver having at least two fingers, the fingers tracking at least one path of a multipath channel, a method includes the steps of forming a finger block of at least two of the two fingers and jointly tracking the fingers of said finger block. The step of jointly tracking includes the steps of generating direction metrics of each of a set of possible directions of joint movement of the fingers of the finger block, selecting one of the direction metrics according to a predetermined criterion, and moving the fingers of the finger block in the directions indicated by the selected direction metric.

Abstract: A communication device including a per finger interference reducer adapted to remove an interference effect of at least one pilot signal from the output of a despreader of the finger.

Abstract: In a receiver receiving a signal, the signal including data which is at least modulated by a cyclic sequence, a method for operating the receiver, the method including the steps of receiving a portion of the signal, the portion being modulated by a predetermined section of the cyclic sequence, receiving an additional portion of the signal, the additional portion being modulated by the predetermined section of the cyclic sequence, jointly processing the portion and the additional portion and producing a set of receiver parameters, the receiver parameters minimizing a predetermined cost function for the predetermined section of the cyclic sequence.

Abstract: A receiver including a signal reception unit, for receiving a signal from a dynamically fading channel, a demodulator, connected to the signal reception unit, for demodulating the received signal, thereby producing a demodulated signal therefrom, a quantizing processor, connected to the demodulator and to the signal reception unit, for analyzing the received signal and for quantizing the demodulated signal, thereby producing a quantized signal, and a decoder, connected to the quantzing processor, for decoding the quantized signal, wherein the quantizing processor normalizes the demodulated signal according to the estimated fading of the received signal.

Abstract: Apparatus and a method for receiving spread-spectrum signals is provided. The method includes the steps of detecting a noisy user signal from a spread-spectrum signal including at least a first user signal (including data therein) and at least one pilot signal, and removing an interference effect of the pilot signal on the first user signal from the noisy user signal thereby to create a noise reduced user signal.

Abstract: A signal processing system includes a plurality of detectors for detecting signals, each detector receiving signals from plural sources; and a processor for receiving the detected signals and producing a reconstruction filter for filtering the detected signals to produce reconstructed source signals in which each source signal is reconstructed without interference from the other source signals. The reconstruction filter is produced such that cross-polyspectra of the reconstructed signals are forced to approach zero.