An Improved Double Iterate Equalize Algorithm for Continuous Phase Modulation

Abstract

The high-speed wireless data transmission business is growing rapidly, but the high-speed data transmission and high spectral efficiency application system have many problems, such as the divergence of the channel will lead to the serious inter symbol interference (ISI). It is therefore necessary to use equalizer to reduce the impact of ISI. In the condition of large channel memory length, when modulating, its complexity may not be accepted. Therefore, it may use a sub-prime but low complexity turbo equalize receiver. Its main idea is separating the channel equalizer, continuous phase modulation (CPM), and the channel decoded operation. It will make double iteration between the equalizer and the demodulator. Experimental simulation indicates that the double iteration algorithm overcomes the shortcoming under the adverse conditions greatly, for example, the channel memory length is too large or there are too many super grid states.