Abstract:

A honeycomb (nonsquare) 16 amplitude phase keying (APK) modulation is proposed. A new dualmode based on honeycomb decision region algorithm (DHDRA) is provided. The proposed algorithm is simulated using a typical shallow underwater acoustic channel. Simulation shows that, more antiinterference and faster convergence are achieved with the constant modulus algorithm (CMA) based on the honeycomb 16APK than that with the square 16QAM, meanwhile. Also, higher convergence speeds and less steady residual errors are got with the proposed dualmode algorithm than the that with the squared decision region algorithm. They have the research value for improving the underwater communication qualities and decreasing the intersymbol interference.

Key words: blind equalization, constant modulus, intersymbol interference