ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE WITH CIRCUIT FOR MEASURING FREQUENCY RESPONSE OF THE COMMUNICATIONS CHANNEL
First Claim
1. A communications device, comprising:
- a demapping and demodulation circuit for processing an OFDM communications signal that had been transmitted along a communications channel, wherein the OFDM communications signal comprises modulated subcarriers carrying communications data forming a data payload and modulated subcarriers carrying a training sequence forming a preamble, wherein the OFDM subcarriers carrying the training sequence have a sample for each subcarrier at a center of a frequency bin using evenly spaced, equal amplitude subcarriers that have a set phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); and
a channel estimate circuit operative for measuring fluctuations within a flat-topped spectrum of the received OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel.
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Accused Products
Abstract
A communications device includes a demapping and demodulation circuit and processes an OFDM communications signal that includes modulated subcarriers carrying communications data forming a data payload and modulated subcarriers carrying a training sequence forming a preamble. Those OFDM subcarriers carrying the training sequence have a sample for each subcarrier at a frequency bin using evenly spaced, equal amplitude subcarriers that have a set phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB). A channel estimate circuit is operative for measuring fluctuations within a flat-top spectrum of the received OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel.
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Citations
25 Claims
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1. A communications device, comprising:
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a demapping and demodulation circuit for processing an OFDM communications signal that had been transmitted along a communications channel, wherein the OFDM communications signal comprises modulated subcarriers carrying communications data forming a data payload and modulated subcarriers carrying a training sequence forming a preamble, wherein the OFDM subcarriers carrying the training sequence have a sample for each subcarrier at a center of a frequency bin using evenly spaced, equal amplitude subcarriers that have a set phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); and a channel estimate circuit operative for measuring fluctuations within a flat-topped spectrum of the received OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A communications system, comprising:
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a transmitter that comprises a modulation and mapping circuit that modulates communications data and a training sequence corresponding to a preamble into a plurality of multiple subcarriers that are orthogonal to each other to form an Orthogonal Frequency Division Multiplexing (OFDM) communications signal having modulated subcarriers carrying the communications data and forming a data payload and modulated subcarriers forming the preamble, wherein the OFDM subcarriers carrying the training sequence have a sample for each subcarrier at a center of a frequency bin using evenly spaced, equal amplitude subcarriers that have a set phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); and a receiver that receives the OFDM communications signal from the transmitter as transmitted along a communications channel and comprising a demapping and demodulation circuit for processing the OFDM communications signal to obtain the communications data, and further comprising a channel estimate circuit operative for measuring fluctuations within a flat-topped spectrum of the received OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of communicating data, comprising:
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receiving communications data to be transmitted and a training sequence corresponding to a preamble; generating an Orthogonal Frequency Division Multiplexing (OFDM) communications signal having modulated subcarriers carrying the communications data forming a data payload and subcarriers carrying training sequences forming the preamble; sampling for each subcarrier at a center of a frequency bin using evenly spaced, equal amplitude subcarriers and setting a phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); transmitting the OFDM communications signal along a communications channel to a receiver; and receiving the OFDM communications signal within the receiver and performing channel estimation of the communications channel by measuring at the receiver fluctuations within a flat-topped spectrum of the OFDM communications signal corresponding to the preamble to reflect the frequency response of the communications channel. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of measuring the response of filter, comprising:
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generating an Orthogonal Frequency Division Multiplexing (OFDM) impulse signal having modulated subcarriers carrying training sequences forming a preamble; sampling for each subcarrier at a center of a frequency bin using evenly spaced, equal amplitude subcarriers and setting a phase of each sinusoid to a specific angle with quadratic phase to form a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); transmitting the OFDM impulse signal along a communications channel to a receiver; and receiving the OFDM communications signal within a filter and performing channel estimation of the communications channel by measuring at the filter fluctuations within a flat-topped spectrum of the OFDM communications signal corresponding to the preamble that reflects the frequency response of the filter.
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Specification