Abstract: Methods and apparatuses of concatenated channel decoding data involving the decoding of soft-channel symbols using a parity-check to generate a plurality of m decoded data symbols according to an (m+1, m) parity check code, and decoding the plurality of m decoded bits according to an (N,K) Reed-Solomon (RS) code over GF (2m) to provide the data. N is a length, measured in symbols of the RS code, and K is message length measured in symbols.

Abstract: A timing estimation system and methodology are provided. In particular, a first pilot is employed in conjunction with three acquisition stages. In the first stage, an attempt is made to observe the leading edge of the correlation curve associated with the first pilot symbol. In the second stage, a determination is made to confirm a leading edge was detected in the first stage by attempting to observe a trailing edge of the correlation curve. Furthermore, during this second stage, a frequency loop is updated to account for frequency offset. The third stage is for observing the trailing edge of the curve if it was not already observed in stage two. Upon detection of receipt of the first pilot, a second pilot can subsequently be employed to acquire fine symbol timing.

Abstract: An apparatus and method for recovering data transmitted in a wireless communication system is claimed. A plurality of signal points, the signal point including a plurality of modulation symbols from a plurality of coded bits, is received. A first subset of signal points for which a bit is equal to a first value and a second subset of signal points for which the bit is equal to a second value is determined. The first and second subsets are signal points from an expanded signal constellation. The probability that the bit is equal to the first value or the second value is determined as a function of the received signal point. A soft decision symbol may then be determined, based on the probability that the bit is equal to the first value or the second value. The soft decision symbols may be represented as log likelihood ratios.

Abstract: Techniques are provided for tracking residual frequency error and phase noise in an OFDM system. At a receiver, each received OFDM symbol is transformed with an FFT to obtain received modulation symbols, which are serialized. A phase locked loop (PLL) operates on the serialized received modulation symbols and provides an independent phase correction value for each received modulation symbol. Each received modulation symbol is corrected with its own phase correction value to obtain a phase-corrected symbol. The phase error in each phase-corrected symbol is detected to obtain a phase error estimate for that phase-corrected symbol. The phase error estimate for each phase-corrected symbol is filtered (e.g., with a second-order loop filter) to obtain a frequency error estimate, which is accumulated to obtain a phase correction value for another received modulation symbol. The phase-corrected symbols are not correlated because independent phase correction values are used for the received modulation symbols.

Abstract: Systems and methods are provided for processing Time Domain Multiplexing (TDM) symbols via delayed correlation in the time domain. In one embodiment, a method is provided for determining synchronization information in an Orthogonal Frequency Division Multiplexing (OFDM) broadcast. The method includes employing a time domain correlation to detect the start of an OFDM super frame and utilizing the time domain correlation to synchronize a receiver to the carrier frequency of the OFDM signal.

Abstract: A novel method and apparatus for efficiently coding and decoding data in a data transmission system is described. A concatenated coding scheme is presented that is easily implemented, and that provides acceptable coding performance characteristics for use in data transmission systems. The inventive concatenated channel coding technique is well suited for small or variable size packet data transmission systems. The technique may also be adapted for use in a continuous mode data transmission system. The method and apparatus reduces the complexity, cost, size and power consumption typically associated with the prior art channel coding methods and apparatuses, while still achieving acceptable coding performance. The present invention advantageously performs concatenated channel coding without the necessity of a symbol interleaver. In addition, the present invention is simple to implement and thereby consumes much less space and power that do the prior art approaches.

Abstract: Techniques are provided for tracking residual frequency error and phase noise in an OFDM system. At a receiver, each received OFDM symbol is transformed with an FFT to obtain received modulation symbols, which are serialized. A phase locked loop (PLL) operates on the serialized received modulation symbols and provides an independent phase correction value for each received modulation symbol. Each received modulation symbol is corrected with its own phase correction value to obtain a phase-corrected symbol. The phase error in each phase-corrected symbol is detected to obtain a phase error estimate for that phase-corrected symbol. The phase error estimate for each phase-corrected symbol is filtered (e.g., with a second-order loop filter) to obtain a frequency error estimate, which is accumulated to obtain a phase correction value for another received modulation symbol. The phase-corrected symbols are not correlated because independent phase correction values are used for the received modulation symbols.

Abstract: An improved channel estimation is disclosed. In one embodiment, initial channel estimation is performed using known training data sequence. The data packet received is demodulated based on the initial channel estimates, de-interleaved and decoded. The decoded data is then is re-encoded, interleaved and modulated to generate additional training symbols for updating the channel estimates throughout the received data packet.

Abstract: The present invention is a novel method and apparatus for efficiently coding and decoding data in a data transmission system. A concatenated coding scheme is presented that is easily implemented, and that provides acceptable coding performance characteristics for use in data transmission systems. The inventive concatenated channel coding technique is well suited for small or variable size packet data transmission systems. The technique may also be adapted for use in a continuous mode data transmission system. The method and apparatus reduces the complexity, cost, size, power consumption typically associated with the prior art channel coding methods and apparatuses, while still achieving acceptable coding performance. The present invention advantageously performs concatenated channel coding without the necessity of a symbol interleaver. In addition, the present invention is simple to implement and thereby consumes much less space and power that do the prior art approaches.

Abstract: An apparatus and method for recovering data transmitted in a wireless communication system is claimed. A plurality of signal points, the signal point comprising a plurality of modulation symbols from a plurality of coded bits, is received. A first subset of signal points for which a bit is equal to a first value and a second subset of signal points for which the bit is equal to a second value is determined. The first and second subsets are signal points from an expanded signal constellation. The probability that the bit is equal to the first value or the second value is determined as a function of the received signal point. A soft decision symbol may then be determined, based on the probability that the bit is equal to the first value or the second value. The soft decision symbols may be represented as log likelihood ratios.

Abstract: A process is described for producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles. An aluminum alloy is used containing 0.5-0.75% by weight Mg, 0.7-0.85% by weight Si, 0.15-0.35% by weight Mn and 0.1-0.3% by weight Fe and the remainder Al and incidental impurities. The alloy is formed into ingot by semi-continuous casting and the cast alloy ingot is subjected to hot rolling and cold rolling, followed by solution heat treatment of the formed sheet. The sheet material is pre-aged by rapidly cooling from an initial pre-aging temperature of at least 80° C. to room temperature at a cooling rate of more than 5° C./hour.

Abstract: A process of producing a shaped article suitable for use as an automotive body panel intended for finishing by painting and, if necessary, baking. The process comprises obtaining a sheet article made of an aluminum alloy of the 2000 or 6000 series in a T4 or T4P temper and that exhibits an increase in hardness after painting and optionally baking, shaping the sheet article by forming to produce an intermediate shaped article, and subjecting the intermediate shaped article to a thermal spiking treatment prior to painting and optionally baking. The thermal spiking treatment involves heating the intermediate shaped article from ambient temperature to a temperature in a range of 150 to 300° C. with or without holding at that temperature for a period of time to enhance the increase in hardness. The process may also include the painting and optionally baking step. The invention includes the shaped articles, either prior to or after painting and optionally baking, produced by the process.

Abstract: A process of producing a shaped article suitable for use as an automotive body panel intended for finishing by painting and, if necessary, baking. The process comprises obtaining a sheet article made of an aluminum alloy of the 2000 or 6000 series in a T4 or T4P temper and that exhibits an increase in hardness after painting and optionally baking, shaping the sheet article by forming to produce an intermediate shaped article, and subjecting the intermediate shaped article to a thermal spiking treatment prior to painting and optionally baking. The thermal spiking treatment involves heating the intermediate shaped article from ambient temperature to a temperature in a range of 150 to 300° C. with or without holding at that temperature for a period of time to enhance the increase in hardness. The process may also include the painting and optionally baking step. The invention includes the shaped articles, either prior to or after painting and optionally baking, produced by the process.

Abstract: A method of producing a sheet article or other elongated product of solution heat treated aluminum alloy substantially free of permanent thermal distortion. The method involves subjecting an article made of a heat-treatable aluminum alloy to a solution heat treatment, cooling the article in a gas from the solutionizing temperature to an upper critical temperature below which precipitation of second phase particles of the alloy may occur, further cooling the article in a gas/liquid from the upper temperature to a lower critical temperature below which precipitation of the components may no longer occur, and optionally additionally cooling the article to a temperature below the lower critical temperature. The cooling of the article in the gas is carried out at a rate of cooling at which the yield strength of the article remains high enough to resist permanent deformation caused by thermal stress generated within the article by the cooling.

Abstract: An aluminum alloy containing the following elements in the stated amounts: 0.6≦Mg≦0.9; 0.25≦Si≦0.6; 0.25≦Cu≦0.9; Fe<0.4; Mn<0.4; the total of the amounts of Cu, Si and Mg being, in atomic weight percent, more than 1.2% and less than 1.8%. These alloys may be subjected to homogenization at about 470 to 560° C. for more than four hours, hot rolling at a temperature in the range of 400 to 580° C., cold rolling, solutionizing at a temperature in the range of 470 to 580° C., and natural aging at ambient temperature. The alloys may then be used as structural components for all aluminum vehicles and may be recycled with other aluminum alloys used in such vehicles.

Abstract: A process of producing an aluminum alloy sheet product suitable for forming into automotive parts and exhibiting reduced roping effects. The process involves producing an aluminum alloy sheet product by direct chill casting an aluminum alloy to form a cast ingot, homogenizing the ingot, hot rolling the ingot to form and intermediate gauge product, cold rolling the intermediate gauge product to form a product of final gauge, and subjecting the final gauge product to a solutionizing treatment by heating the product to a solutionizing temperature, followed by a pre-aging step involving cooling the product to a coiling temperature above 50.degree. C., coiling the cooled product at the coiling temperature, and cooling the coiled final gauge product from the coiling temperature above 50.degree. C. to ambient temperature at a rate less than about 10.degree. C. per hour to improve T8X temper characteristics of the product.

Abstract: A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can by used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.

Abstract: A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can be used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.