Probabilistically shaped orthogonal frequency division multiplexing
First Claim
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1. A method of optical communication, implemented at a transmitter in an optical communication network, comprising:
- mapping input data to complex symbols using a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme;
converting the complex symbols from serial data to parallel data to obtain parallel complex symbols;
generating an OFDM signal from the parallel complex symbols, wherein the OFDM signal is a Discrete Fourier Transform-Spread (DFT-S) OFDM signal, and wherein the generating of the OFDM signal from the parallel complex symbols includes;
performing an L-point Fast Fourier Transform (FFT) on the parallel complex symbols to obtain an L-point DFT-S signal, andperforming an N-point Inverse Fast Fourier Transform (IFFT) on the L-point DFT-S signal to obtain the DFT-S OFDM signal, wherein N is equals to a number of subcarriers of the DFT-S OFDM signal and wherein N and L are integers;
adding a cyclic prefix to the OFDM signal;
converting the OFDM signal with the cyclic prefix from parallel data to serial data to obtain a serial OFDM signal;
generating a real-value OFDM signal from the serial OFDM signal; and
transmitting the real-value OFDM signal.
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Abstract
An optical signal transmission can use probabilistically shaped technique to improve performance and increase the transmission capacity. For instance, a 30-Gbit/s/λ probabilistically shaped (PS) 1024-QAM DFT-S OFDM was experimentally demonstrated over 40-km SSMF in an intensity modulation-direct detection system. The Achievable Information Rate (AIR) 9.5344-bits/QAM symbol of PS-1024-QAM modulation is first achieved in the experiment and shows feasibility for OFDM.
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Citations
20 Claims
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1. A method of optical communication, implemented at a transmitter in an optical communication network, comprising:
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mapping input data to complex symbols using a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme; converting the complex symbols from serial data to parallel data to obtain parallel complex symbols; generating an OFDM signal from the parallel complex symbols, wherein the OFDM signal is a Discrete Fourier Transform-Spread (DFT-S) OFDM signal, and wherein the generating of the OFDM signal from the parallel complex symbols includes; performing an L-point Fast Fourier Transform (FFT) on the parallel complex symbols to obtain an L-point DFT-S signal, and performing an N-point Inverse Fast Fourier Transform (IFFT) on the L-point DFT-S signal to obtain the DFT-S OFDM signal, wherein N is equals to a number of subcarriers of the DFT-S OFDM signal and wherein N and L are integers; adding a cyclic prefix to the OFDM signal; converting the OFDM signal with the cyclic prefix from parallel data to serial data to obtain a serial OFDM signal; generating a real-value OFDM signal from the serial OFDM signal; and transmitting the real-value OFDM signal. - View Dependent Claims (2, 3, 4)
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5. A method of optical communication, implemented at a receiver in an optical communication network, comprising:
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receiving and converting a real-value OFDM signal to a complex-value OFDM signal; removing cyclic prefix from the complex-value OFDM signal; converting, after removing the cyclic prefix, the complex-value OFDM signal from serial data to parallel data to obtain a parallel OFDM signal; generating, from the parallel OFDM signal, complex symbols based on a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme, wherein the generating of the complex symbols comprises; performing an N-point Fast Fourier Transform (FFT) on the parallel OFDM signal to obtain intermediate complex symbols, wherein N is equal to a number of subcarriers of the OFDM signal; performing post-equalization on the intermediate complex symbols to obtain parallel equalized complex symbols; converting the parallel equalized complex symbols to serial complex symbols; and performing decision directed least mean square (DD-LMS) equalization on the serial complex symbols to obtain the complex symbols; and de-mapping the complex symbols using a probabilistic shaped quadrature amplitude demodulation scheme to obtain an output signal. - View Dependent Claims (7, 8)
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6. A method of optical communication, implemented at a receiver in an optical communication network, comprising:
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receiving and converting a real-value OFDM signal to a complex-value OFDM signal; removing cyclic prefix from the complex-value OFDM signal; converting, after removing the cyclic prefix, the complex-value OFDM signal from serial data to parallel data to obtain a parallel OFDM signal; generating, from the parallel OFDM signal, complex symbols based on a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme, wherein the OFDM signal is a Discrete Fourier Transform-Spread (DFT-S) OFDM signal, and wherein the generating of the complex symbols comprises; performing an N-point Fast Fourier Transform (FFT) on the parallel OFDM signal to obtain DFT-S complex symbols, wherein N is equal to a number of subcarriers of the DFT-S OFDM signal; performing post-equalization on the DFT-S complex symbols to obtain equalized DFT-S complex symbols; performing an L-point Inverse Fourier Transform (IFFT) on the equalized DFT-S complex symbols to obtain parallel equalized complex symbols; converting the parallel equalized complex symbols to serial complex symbols; and performing decision directed least mean square (DD-LMS) equalization on the serial complex symbols to obtain the complex symbols; and de-mapping the complex symbols using a probabilistic shaped quadrature amplitude demodulation scheme to obtain an output signal. - View Dependent Claims (9, 10)
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11. A wireless communication device comprising a processor and a memory, wherein the memory stores instructions that, when executed, cause the processor to:
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map input data to complex symbols using a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme; convert the complex symbols from serial data to parallel data to obtain parallel complex symbols; generate an OFDM signal from the parallel complex symbols, wherein the OFDM signal is a Discrete Fourier Transform-Spread (DFT-S) OFDM signal, and wherein the instructions to generate the OFDM signal from the parallel complex symbols includes instructions to; perform an L-point Fast Fourier Transform (FFT) on the parallel complex symbols to obtain an L-point DFT-S signal, and perform an N-point Inverse Fast Fourier Transform (IFFT) on the L-point DFT-S signal to obtain the DFT-S OFDM signal, wherein N is equals to a number of subcarriers of the DFT-S OFDM signal and wherein N and L are integers; add a cyclic prefix to the OFDM signal; convert the OFDM signal with the cyclic prefix from parallel data to serial data to obtain a serial OFDM signal; generate a real-value OFDM signal from the serial OFDM signal; and transmit the real-value OFDM signal. - View Dependent Claims (12, 13, 14)
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15. A wireless communication device comprising a processor and a memory, wherein the memory stores instructions that, when executed, cause the processor to:
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receive and converting a real-value OFDM signal to a complex-value OFDM signal; remove cyclic prefix from the complex-value OFDM signal; convert, after removing the cyclic prefix, the complex-value OFDM signal from serial data to parallel data to obtain a parallel OFDM signal; generate, from the parallel OFDM signal, complex symbols based on a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme, wherein the instructions to generate the complex symbols comprises instructions to; perform an N-point Fast Fourier Transform (FFT) on the parallel OFDM signal to obtain intermediate complex symbols, wherein N is equal to a number of subcarriers of the OFDM signal; perform post-equalization on the intermediate complex symbols to obtain parallel equalized complex symbols; convert the parallel equalized complex symbols to serial complex symbols; and perform decision directed least mean square (DD-LMS) equalization on the serial complex symbols to obtain the complex symbols; and de-map the complex symbols using a probabilistic shaped quadrature amplitude demodulation scheme to obtain an output signal. - View Dependent Claims (16, 17)
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18. A wireless communication device comprising a processor and a memory, wherein the memory stores instructions that, when executed, cause the processor to:
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receive and converting a real-value OFDM signal to a complex-value OFDM signal; remove cyclic prefix from the complex-value OFDM signal; convert, after removing the cyclic prefix, the complex-value OFDM signal from serial data to parallel data to obtain a parallel OFDM signal; generate, from the parallel OFDM signal, complex symbols based on a probabilistic shaped quadrature amplitude modulation (PS-QAM) scheme, wherein the OFDM signal is a Discrete Fourier Transform-Spread (DFT-S) OFDM signal, and wherein the instructions to generate the complex symbols comprises instructions to; perform an N-point Fast Fourier Transform (FFT) on the parallel OFDM signal to obtain DFT-S complex symbols, wherein N is equal to a number of subcarriers of the DFT-S OFDM signal; perform post-equalization on the DFT-S complex symbols to obtain equalized DFT-S complex symbols; perform an L-point Inverse Fourier Transform (IFFT) on the equalized DFT-S complex symbols to obtain parallel equalized complex symbols; convert the parallel equalized complex symbols to serial complex symbols; and perform decision directed least mean square (DD-LMS) equalization on the serial complex symbols to obtain the complex symbols; and de-map the complex symbols using a probabilistic shaped quadrature amplitude demodulation scheme to obtain an output signal. - View Dependent Claims (19, 20)
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Specification