Blind equalization of dual subcarrier ofdm signals
AssigneeZte Corporation
InventorsJianjun Yu, Fan Li
Life of this patent
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Abstract
A dual-polarization, 2-subcarriers code orthogonal, orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 2-subcarriers OFDM signal as a 9-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method.
Claims27
A method for recovering data from a two-subcarrier orthogonal frequency division multiplexed (OFDM) signal in which each subcarrier is modulated using a Quadrature Amplitude Modulation (QAM) constellation, comprising:
- receiving the two-subcarrier OFDM signal;
- converting the two-subcarrier OFDM signal into a time domain QAM signal;
- and
- performing blind equalization of the time domain QAM signal to recover the data.
An optical receiver apparatus for recovering data from a two-subcarrier orthogonal frequency division multiplexed (OFDM) signal in which each subcarrier is modulated using a Quadrature Amplitude Modulation (QAM) constellation, comprising:
- an optical receiver module that receives the two-subcarrier OFDM signal;
- a receiver processing module that processes the two-subcarrier OFDM signal as a QAM signal to generate a modulus signal;
- and
- a transform module that applies an orthogonal transform to the modulus signal to recover the data.
An optical communication apparatus, comprising:
- a memory that stores instructions;
- and
- a processor that reads the instructions from the memory and implements a method of optical reception of a two-subcarrier orthogonal frequency division multiplexed (OFDM) signal in which each subcarrier is modulated using a Quadrature Amplitude Modulation (QAM) constellation, the method causing the processor to:
- receive the two-subcarrier OFDM signal;
- convert the two-subcarrier OFDM signal into a time domain Quadrature Amplitude Modulation (QAM) signal;
- and
- perform blind equalization of the time domain QAM signal to recover the data.
An optical communication system, comprising:
- an optical transmission apparatus transmits, over the optical transmission medium, a two-subcarrier orthogonal frequency division multiplexed (OFDM) signal in which each subcarrier is modulated using a Quadrature Amplitude Modulation (QAM) constellation comprising information bits without transmitting a training sequence and a pilot signal;
- and
- an optical receiver apparatus that:
- receives the two-subcarrier OFDM signal;
- processes the two-subcarrier OFDM signal as a QAM signal to generate a modulus signal;
- and
- applies an orthogonal transform to the modulus signal to recover the information bits.
Dependencies are inferred from the claim text.