Apparatus, and associated method, for detecting packets
First Claim
1. A method for detecting a packet in multiple signals received in parallel from at least two transmission antennas, the method being characterized by steps of:
- computing the power-normalized auto-correlations of the received signals tuned on the periodicity of short training symbols, said short training symbols having time periods shorter than one OFDM symbol;
determining whether the sum of the moduli of the power-normalized, auto-correlation exceeds a first predetermined threshold;
upon a determination that the sum of the moduli of a power-normalized, auto-correlation exceeds the first predetermined threshold, computing the cross-correlations between the received signals and the aperiodic sequences in a selected time window, said time window sliding in time for a quantity larger than the variance of the first predetermined threshold crossing instant;
computing the maximum value of the sum of the moduli of the cross-correlations;
determining whether the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold; and
upon a determination that the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold, identifying a packet as received.
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Accused Products
Abstract
In a robust system and method for detecting packets in SISO and MIMO broadband multicarrier transmission, a packet detector computes continuously the sum of the moduli of the power-normalized auto-correlations of a sequence of received signals (204), tuned on the periodicity of the training symbols. When the power-normalized auto-correlation exceeds a first predetermined threshold (206), then the maximum value of the sum of the moduli of all the cross-correlations between the received signals and the M aperiodic sequences is computed in a given time window (208), sliding in time from −c0 to c0. A packet is identified as received (212) when the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold (210).
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Citations
20 Claims
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1. A method for detecting a packet in multiple signals received in parallel from at least two transmission antennas, the method being characterized by steps of:
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computing the power-normalized auto-correlations of the received signals tuned on the periodicity of short training symbols, said short training symbols having time periods shorter than one OFDM symbol; determining whether the sum of the moduli of the power-normalized, auto-correlation exceeds a first predetermined threshold; upon a determination that the sum of the moduli of a power-normalized, auto-correlation exceeds the first predetermined threshold, computing the cross-correlations between the received signals and the aperiodic sequences in a selected time window, said time window sliding in time for a quantity larger than the variance of the first predetermined threshold crossing instant; computing the maximum value of the sum of the moduli of the cross-correlations; determining whether the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold; and upon a determination that the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold, identifying a packet as received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for detecting a packet in multiple signals received in parallel from at least two transmission antennas, the apparatus being characterized by:
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a first computational portion configured for computing the power-normalized auto-correlations of the received signals tuned on the periodicity of short training symbols, said short training symbols having time periods shorter than one OFDM symbol; a first comparator configured for determining when the sum of the moduli of the power-normalized, auto-correlation exceeds a first predetermined threshold; a second computational portion configured, upon a determination that the sum of the moduli of a power-normalized, auto-correlation exceeds the first predetermined threshold, for computing the cross-correlations between the received signals and the aperiodic sequences in a selected time window, said time window sliding in time for a quantity larger than the variance of the first predetermined threshold crossing instant; and a second comparator configured for computing the maximum value of the sum of the moduli of the cross-correlations, and for determining when the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold, and upon a determination that the maximum value of the sum of the moduli of the cross-correlations exceeds a second predetermined threshold, for identifying a packet as received. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification