Lucent Technologies Inc.

Jose Luis Paredes

Juan G Gonzalez

Salim Manji

Walid Ahmed

The present invention provides systems and methods for adaptively decoding transmitted frames efficiently in non-Gaussian, non-stationary environments. One such system comprises a decoder adapted to decode a received transmission frame using a decoding scheme, a channel assessment unit for sensing channel characteristics, and a tuning unit for adjusting the decoding scheme based, at least in part, on channel characteristics sensed by the channel assessment unit.

Systems and methods for adaptively decoding transmitted frames

The present invention provides systems and methods for correcting errors in a received frame. The present invention introduces diversity into an error detection and correction system at the receiver side by decoding a received frame using a plurality of decoding schemes. Each of these schemes are optimized for a different set of underlying assumptions. The schemes may be optimized to account for various types of noise including, not limited to, Gaussian noise and impulsive noise. The plurality of decoded frames are then validated using an outer decoder to choose a valid frame from candidate decoded frames. By including a plurality of decoders using a plurality of decoding schemes, the error detection and correction system may accurately detect and correct errors in a constantly changing environment having constantly changing noise patterns.

Systems and methods for correcting errors in a received frame

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.

Method and system for processing a signal

A symbol synchronizer comprises a distance metric computation module for computing a metric from received samples using a distance metric function within a symbol sampling period and based on a timing signal for each of the possible symbols in a constellation, a control signal computation module for selecting a smallest and a second smallest metrics, producing a difference by subtracting the smallest metric from the second smallest metric, and deriving a control signal from the difference, and a voltage-control clock for producing the timing signal based on the control signal.

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Merida, Venezuela

Jose Luis Paredes