ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) COMMUNICATIONS DEVICE AND METHOD THAT INCORPORATES LOW PAPR PREAMBLE AND RECEIVER CHANNEL ESTIMATE CIRCUIT
First Claim
1. A communications device, comprising:
- a demapping and demodulation circuit as a Fast Fourier Transform (FFT) circuit and subcarrier demapper 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 that includes a long sync sequence for acquisition, detection, frequency and channel estimation and having a extended guard interval (GI), wherein the OFDM subcarriers carrying the training sequence has a quadratic modulation applied to those subcarriers to produce a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); and
a channel estimate circuit positioned to receive signals after processing within said FFT circuit and subcarrier demapper circuit, wherein said channel estimate circuit is operative with said FFT and subcarrier demapper circuit for estimating channel characteristics of the communications channel based on splitting the extended guard interval from the long sync sequence and processing into values that represent the inverse low PAPR preamble as plus or minus one (±
1) values in a real or imaginary component as adds and subtracts.
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Accused Products
Abstract
A communications device includes a demapping and demodulation circuit that demaps and demodulates an OFDM communications signal as modulated subcarriers carrying communications data and modulated subcarriers carrying a training sequence forming a preamble that includes a long sync sequence for channel and frequency offset estimation having a extended guard interval (GI). The OFDM subcarriers carrying the training sequence have a quadratic modulation to produce a low peak-to-average power (PAPR) preamble with PAPR of approximately 2.6 decibels (dB). A channel estimate circuit is positioned to receive signals after processing within a FFT circuit and subcarrier demapper circuit and estimates the channel characteristics of the communications channel based on splitting the extended guard interval from the long sync sequence and processing into values that represent the low PAPR preamble as plus or minus one (±1) values in a real or imaginary component as adds and subtracts.
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Citations
24 Claims
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1. A communications device, comprising:
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a demapping and demodulation circuit as a Fast Fourier Transform (FFT) circuit and subcarrier demapper 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 that includes a long sync sequence for acquisition, detection, frequency and channel estimation and having a extended guard interval (GI), wherein the OFDM subcarriers carrying the training sequence has a quadratic modulation applied to those subcarriers to produce a low peak-to-average power ratio (PAPR) preamble with about a PAPR value of 2.6 decibels (dB); and a channel estimate circuit positioned to receive signals after processing within said FFT circuit and subcarrier demapper circuit, wherein said channel estimate circuit is operative with said FFT and subcarrier demapper circuit for estimating channel characteristics of the communications channel based on splitting the extended guard interval from the long sync sequence and processing into values that represent the inverse low PAPR preamble as plus or minus one (±
1) values in a real or imaginary component as adds and subtracts. - View Dependent Claims (2, 3, 4)
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5. 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 preamble includes a long sync sequence for acquisition, detection, frequency and channel estimation and having a extended guard interval (GI), wherein said modulation and mapping circuit applies a quadratic modulation to the subcarriers carrying the training sequences to produce 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 as a Fast Fourier Transform (FFT) circuit and subcarrier demapper circuit for processing the OFDM communications signal to obtain the communications data, and further comprising a channel estimate circuit positioned within the receiver to receive signals after processing within said FFT circuit and subcarrier demapper circuit, wherein the channel estimate circuit is operative with the FFT and subcarrier demapper circuit for estimating channel characteristics of the communications channel based on splitting the extended guard interval from the long sync sequence and processing into values that represent the inverse low PAPR preamble as plus or minus one (±
1) values in a real or imaginary component as adds and subtracts within the receiver. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. 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, wherein the preamble includes a long sync sequence for channel and fine frequency offset estimation having a extended guard interval (GI); applying a quadratic phase modulation to subcarriers carrying the training sequences to produce 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 splitting the extended guard interval from the long sync sequence and processing into values that represent the inverse low PAPR preamble as plus or minus one (±
1) values in a real or imaginary component as adds and subtracts for channel estimation. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification