Managing spectra of modulated signals in a communication network
First Claim
1. A method for operating a communicating station in order to transmit information through a communication medium using a set of channels, wherein the channels have respective carrier frequencies, the method comprising:
- determining a list of one or more of the carrier frequencies over which transmissions are to be attenuated;
encoding information bits according to an error correction code in order to obtain coded bits, wherein the coded bits represent the received information bits with redundancy;
interleaving the coded bits to obtain interleaved bits;
mapping blocks of the interleaved bits to corresponding sets of complex numbers, wherein each set of complex numbers includes one complex number for each of the carrier frequencies;
modifying each set of complex numbers by attenuating one or more of the complex numbers in the set that correspond to the one or more carrier frequencies on the list, wherein said attenuating includes scaling the one or more complex numbers so that their amplitudes are less than a predetermined amplitude level;
computing an inverse Fourier transform of each modified set of complex numbers to obtain a sequence of time-domain samples; and
transmitting a time-domain signal over the communication medium based on the sequence of time-domain samples.
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Accused Products
Abstract
Information is modulated onto frequency components of a signal. The resulting modulated signal includes at least some redundancy in frequency enabling a portion of the information modulated onto selected frequency components to be recovered from fewer than all of the selected frequency components. Controlling the spectrum of the modulated signal includes enabling the amplitude of at least some frequency components of the modulated signal to be set below a predetermined amplitude used for modulating the information.
396 Citations
27 Claims
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1. A method for operating a communicating station in order to transmit information through a communication medium using a set of channels, wherein the channels have respective carrier frequencies, the method comprising:
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determining a list of one or more of the carrier frequencies over which transmissions are to be attenuated; encoding information bits according to an error correction code in order to obtain coded bits, wherein the coded bits represent the received information bits with redundancy; interleaving the coded bits to obtain interleaved bits; mapping blocks of the interleaved bits to corresponding sets of complex numbers, wherein each set of complex numbers includes one complex number for each of the carrier frequencies; modifying each set of complex numbers by attenuating one or more of the complex numbers in the set that correspond to the one or more carrier frequencies on the list, wherein said attenuating includes scaling the one or more complex numbers so that their amplitudes are less than a predetermined amplitude level; computing an inverse Fourier transform of each modified set of complex numbers to obtain a sequence of time-domain samples; and transmitting a time-domain signal over the communication medium based on the sequence of time-domain samples. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A communicating station including a system for transmitting information through a communication medium using a set of channels, wherein the channels have respective carrier frequencies, the system comprising:
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memory for storing a list of one or more of the carrier frequencies over which transmissions are to be attenuated; an encoding unit configured to encode information bits according to an error correction code in order to obtain coded bits, wherein the coded bits represent the received information bits with redundancy; an interleaver configured to interleave the coded bits to obtain interleaved bits; a modulation module configured to; map blocks of the interleaved bits to corresponding sets of complex numbers, wherein each set of complex numbers includes one complex number for each of the carrier frequencies; modify each set of complex numbers by attenuating one or more of the complex numbers in the set that correspond to the one or more carrier frequencies on the list, wherein said attenuating includes scaling the one or more complex numbers so that their amplitudes are less than a predetermined amplitude level; and compute an inverse Fourier transform of each modified set of complex numbers to obtain a sequence of time-domain samples. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification