Abstract: A system for maintaining orthogonality among a plurality of spread-spectrum signals arriving at a base station from a plurality of remote units. Each spread-spectrum signal of the plurality of spread-spectrum signals from each remote unit of the plurality of remote units is transmitted as a packet having a header followed by data. A base station sends a plurality of adjustment signals over a communications channel to the plurality of remote units, respectively. At each remote unit, a circuit selects, from the plurality of adjustment signals, a received-adjustment signal designated for each remote unit. A chip-sequence generator, located at each remote unit, generates a chip-sequence signal assigned to a respective remote unit and, responsive to the adjustment signal, adjusts timing of a chip-sequence signal generated by the chip-sequence generator.

Abstract: A multichannel-spread-spectrum system for communicating a plurality of data-sequence signals from a plurality of data channels using parallel chip-sequence signals in which fewer than all of the channels include header information. A header device concatenates a header to a first data-sequence signal on a first channel. Data-sequence signals in parallel channels are sent without a header, and are timed from the header in the first channel.

Abstract: An improvement to a receiver for receiving multiple rays, due to multipath, of a received spread-spectrum signal having a chip-sequence signal with a chip rate embedded therein. The received spread-spectrum signal is sampled by an analog-to-digital converter at approximately twice the chip rate and then the samples are shifted in a shift register. The shift register shifts the chips of the underlying chip-sequence signal at approximately twice the chip rate. A matched filter includes an adder tree which, in cooperation with the shift register, forms an impulse response matched to the chip-sequence signal. The adder tree detects initially the chip-sequence signal embedded in the first ray, and outputs a first correlation signal. The adder tree then detects the chip-sequence signal embedded in the second ray, and outputs a second correlation signal. The adder tree continues to detect the chip-sequence signal of subsequent rays, and outputs subsequent correlation signals.

Abstract: A fuzzy-logic spread-spectrum adaptive power control system comprising a base station and a plurality of remote units. The base station receives a spread-spectrum signal, and samples the despread spread-spectrum signal at a peak correlation time of the data channel, and at a non-peak correlation time of the data channel. This in turn generates a signal level and a noise level, respectively. A signal-to-noise ratio calculator generates a signal-to-noise ratio from the signal level and the noise level. A fuzzy-logic controller compares the signal-to-noise ratio to a set of predetermined thresholds, and using a state machine, generates a control signal which is thereby transmitted to the remote unit, indicating the amount by which to increase or decrease transmitted power. Each remote unit demodulates the control signal, and a transmitter controller adjusts a power level of the remote-unit spread-spectrum transmitter.

Abstract: A system and method using a Costas loop to effect accelerated convergence with minimal system complexity. The system comprises an in-phase-limiter and a quadrature-phase limiter, operatively coupled to an EXCLUSIVE-OR gate, for exclusively-ORing an in-phase-sign signal and a quadrature-phase-sign signal to output a first error signal, responsive to the signals having same signs, or a second error signal, responsive to the signals having different signs. An AGC circuit, operatively coupled to an output of the EXCLUSIVE-OR gate, increases and decreases a voltage level of an AGC signal responsive to two consecutive first or second error signals and consecutive dissimilar error signals, respectively. A voltage-controlled oscillator, operatively coupled to an output of the AGC circuit and responsive to the increased or decreased voltage level, changes the frequency of a voltage-controlled-oscillator output signal.