Cumulant based automatic modulation classification of QPSK, OQPSK, π/4-QPSK and 8-PSK in MIMO environment
Dibyajyoti Das, Abhinav Anand, Prabin Kumar Bora, Ratnajit Bhattacharjee · 2016
This work proposes an automatic modulation classification (AMC) algorithm to classify QPSK, OQPSK, π/4-QPSK and 8-PSK in the MIMO environment. The proposed method employs a zero forcing equalizer (ZFE) to estimate the transmitted signal. Two different cases are considered regarding the channel state information (CSI): (1) Perfect CSI and (2) Effect of erroneous channel estimation on modulation classification of the MIMO signal. To classify QPSK, OQPSK, π/4-QPSK and 8-PSK, the following steps need to be performed: (1) The fourth order zero conjugate cumulant of the estimated stream of any transmitting antennas is used to distinguish QPSK (or OQPSK) and 8-PSK, (2) The fourth order zero conjugate cumulant of the estimated source symbols is used to distinguish π/4-QPSK and QPSK (or OQPSK), (3) The fourth order zero conjugate cumulant of the estimated stream of any transmitting antennas is used to distinguish 8-PSK and π/4-QPSK and (4) The fourth order zero conjugate cumulant of the finite difference (backward or forward) of the estimated source symbols is used to distinguish QPSK and OQPSK.