Abstract: In accordance with the present invention, a method of prevention of defects in uniform coatings is proposed. The method comprises decelerating the advancement of the dewetting front of a coating attained by externally controlling the wettability and the size of a buffer zone at the boundary of the coating area. The surface of the buffer zone should have better wettability with respect to the fluid in the coating than the surface of the coating area.

Abstract: A method and apparatus implementing the method, of selecting a bit load b for a channel in a carrier system. The carrier system encodes data based on a constellation of points. Each point represents a tuple of data. The constellation has a self-similarity property. The bit load for the channel is selected based on the self-similarity property of the constellation. In an alternate embodiment, the method and apparatus are used to determine the bit load of the sub-channels in a multi-carrier system.

Abstract: In accordance with the present invention, there is provided a method of generating, for a given natural q, a set of q complex sequences of a constant envelope DFT-transformed into sequences also of a constant envelope. It is shown that these sequences are transformed into themselves upon applying the DFT twice. A digital communications method with enhanced bandwidth and transmitted power utilization employing these sequences as basic transmission objects is described. Finally, a method of generating complex sequences identical to their discrete spectra is described.

Abstract: The present invention includes a method for selecting appropriate forward error correction and automatic repeat request parameters for protection of a multicarrier communication channel. The multicarrier communication channel may be wired or wireless. Particular aspects of the present invention are described in the claims, specification and drawings.

Abstract: A method, and apparatus implementing the method, encodes bits to be transmitted over a channel. The channel may be a single carrier or a multi-carrier channel. Bits are encoded based on a constellation that has a self-similarity property and also has an improved bit error rate. The constellation was iteratively generated using a mirroring technique. In addition, a method, and apparatus, implementing the method, decodes bits that were received from a channel. The bits are decoded for a constellation that has a self-similarity property and that was generated using the mirroring technique.

Abstract: A method and apparatus determines an uncoded bit error rate pb based on a target symbol error rate ?s. The uncoded bit error rate pb is determined based on a weighted series expansion of the target symbol error rate ?s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K. The maximum number of symbol errors t and the number of symbols in the information field K is selected such that the uncoded bit error rate pb that produces a symbol error rate that is less than or equal to the target symbol error rate ?s is largest.

Abstract: A method and apparatus selects forward error correction parameters in a channel having a plurality of subchannels in a multicarrier communications system. A signal-to-noise ratio representing a subset of the subchannels is determined. A number (s) of discrete multi-tone symbols in a forward-error-correction frame, a number (z) of forward-error-correction control symbols in the discrete multitone symbol associated with the signal-to-noise ratio, a number of subchannels associated with the signal-to-noise ratio, and a net coding gain for different values of s, z, signal-to-noise ratios and numbers of subchannels is stored in a table. Forward error correction parameters of the channel are selected based on the net coding gain by applying an approximation to a subset of values in the table.

Abstract: In accordance with the present invention, there are provided methods for estimating the level of interferers and the level of a useful signal in a spectral window of a given bandwidth in a communications channel in a complex multipath propagation environment. The first method of estimating the level of interferers comprises generating and transmitting several sets of sine waves on the Nyquist frequency. Each set is characterized by a certain phase so that the sequence of phase values evenly spans the interval (0, 2?) radians. The second method comprises generating and transmitting several sets of sine waves of the same phase, with frequencies evenly spanning a vicinity of the Nyquist frequency. The method of estimating the level of a useful signal comprises transmitting several repetitions of the signal used for actual data transmission and processing it by the receiving station.

Abstract: In one embodiment, a method and apparatus increases a bit load of a multicarrier system comprising a channel having a plurality of subchannels. A bit load is determined for at least one subchannel based on a target symbol error rate ?S a maximum number of symbol errors that can be corrected t, a number of symbols in an information field K, and a maximum number of transmissions k, and a number of bits per subchannel. The maximum number of symbol errors t, the number of symbols in the information field K and the maximum number of transmissions k, is selected such that a net coding gain is increased. In another embodiment, a method determines data flow for a channel having a plurality of subchannels in a multi-carrier system.

Abstract: In accordance with the present invention, there are provided peak-to-average power ratio optimal phase shifters for multi-carrier communications. An optimal shifter is shown to be a complex, constant envelope sequence mapped by a multi-tone transformation used to another complex, constant envelope sequence. In the case of the inverse discrete Fourier transform being the multi-tone transformation, a family of principal shifters of the form z(r)=exp(±j*?*p*r2/q), where j2=?1, 0?r<q, q is a number of subcarriers, and p and q are mutually prime integers of different parity, has been analytically constructed. These phase shifters outperform the best existing phase shifter by as much as 2.6 dB.

Abstract: In accordance with the present invention, there are provided peak-to-average power ratio optimal phase shifters for multi-carrier communications. An optimal shifter is shown to be a complex, constant envelope sequence mapped by a multi-tone transformation used to another complex, constant envelope sequence. In the case of the inverse discrete Fourier transform being the multi-tone transformation, a family of principal shifters of the form z(r)=exp(±j*?*p*r2/q), where j2=?1, 0?r<q, q is a number of subcarriers, and p and q are mutually prime integers of different parity, has been analytically constructed. These phase shifters outperform the best existing phase shifter by as much as 2.6 dB.

Abstract: There is provided a method of generating pulses with enhanced bandwidth occupancy. A bandwidth occupancy criterion in the form of a variational problem is introduced. This problem has an analytical solution yielding an optimum termed the SO-pulse. A low-complexity approximation of this pulse is given by the logistic equation and is termed the L-pulse. Finally, a new trapezoidal pulse termed the phi-pulse that provides an optimum for the bandwidth occupancy criterion on a subclass of pulses generated by passing a unit area impulse through a sequence of sliding summers is introduced. Simulations of BER tests show that these new pulses are superior to the standard ones used in digital communications.

Abstract: In accordance with the present invention, there is provided a stealth communication method for transmitting a proprietary message using an information-bearing noise having an internal structure associated with the message. The spectral properties of the information-bearing noise are indistinguishable from those of the noise in the communication channel. This information-bearing noise can be combined with a non-random decoy signal.

Abstract: In accordance with the present invention, there are provided methods for estimating the level of interferers and the level of a useful signal in a spectral window of a given bandwidth in a communication channel in a complex multipath propagation environment. The first method of estimating the level of interferers comprises generating and transmitting several sets of sine waves on the Nyquist frequency. Each set is characterized by a certain phase so that the sequence of phase values uniformly sweeps the interval (0, 360).The second method comprises generating and transmitting several sets of sine waves of the same phase, with frequencies uniformly sweeping a vicinity of the Nyquist frequency. The method of estimating the level of a useful signal comprises transmitting several repetitions of the signal used for actual data transmission and processing it by the receiving station.

Abstract: The present invention includes a method for selecting appropriate forward error correction and automatic repeat request parameters for protection of a multicarrier communication channel. The multicarrier communication channel may be wired or wireless. Particular aspects of the present invention are described in the claims, specification and drawings.

Abstract: The present invention includes alternative methods for selecting forward error correction parameters to be used in multi channel communications. Method embodying aspects of the present invention may include acquiring signal to noise ratio data for a set of communications channels, counting, estimating or identifying channels to carry data, computing an average signal to noise ratio for channels used and selecting set(s) of FEC parameters. It may predicting net SNR gains and storing these predictions as splines or in interpolation tables. This invention is specifically applicable to Reed-Solomon encoding for FEC and selecting the Reed-Solomon parameters S and R/S. Symbol sets, represented by S may consist of dmt symbols or of data carried by multiple channels in one transmission interval. The computations for selecting parameters may include adjusting the average signal to noise ratio by a safety margin.

Abstract: The present invention includes a method for selecting appropriate forward error correction and automatic repeat request parameters for protection of a multicarrier communication channel. The multicarrier communication channel may be wired or wireless. Particular aspects of the present invention are described in the claims, specification and drawings.

Abstract: A method and apparatus determines an uncoded bit error rate pb based on a target symbol error rate &egr;s. The uncoded bit error rate pb is determined based on a weighted series expansion of the target symbol error rate &egr;s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K. The maximum number of symbol errors t and the number of symbols in the information field K is selected such that the uncoded bit error rate pb that produces a symbol error rate that is less than or equal to the target symbol error rate &egr;s is largest.

Abstract: A method and apparatus selects forward error correction parameters in a channel having a plurality of subchannels in a multicarrier communications system. A signal-to-noise ratio representing a subset of the subchannels is determined. A number (s) of discrete multi-tone symbols in a forward-error-correction frame, a number (z) of forward-error-correction control symbols in the discrete multitone symbol associated with the signal-to-noise ratio, a number of subchannels associated with the signal-to-noise ratio, and a net coding gain for different values of s, z, signal-to-noise ratios and numbers of subchannels is stored in a table. Forward error correction parameters of the channel are selected based on the net coding gain by applying an approximation to a subset of values in the table.

Abstract: In one embodiment, a method and apparatus increases a bit load of a multicarrier system comprising a channel having a plurality of subchannels. A bit load is determined for at least one subchannel based on a target symbol error rate &egr;S, a maximum number of symbol errors that can be corrected t, a number of symbols in an information field K, and a maximum number of transmissions k, and a number of bits per subchannel. The maximum number of symbol errors t, the number of symbols in the information field K and the maximum number of transmissions k, is selected such that a net coding gain is increased.