Writing an equaliser code for QPSK communication in MATLAB

I have a MATLAB code for underwater communication system where I give audio signal as an input to the transmitter code. I carry out following processes on the audio signal :- 1. MELP Speech encoding. 2. QPSK modulation 3. Carrier modulation The output of transmitter code is given to receiver code which performs:- 1. Carrier demodulation. 2. QPSK demodulation 3. MELP speech decoding. Presently the code is working in MATLAB without any channel in between. I want to make the code work in acoustic underwater environment where water tank is a channel. The trasnmitter code output can be given to transducer suspended in the tank using LabView and power amplifier. On the other side, signal is picked up by hydrophone and the same is pre-amplified and given to my receiver code as a labview file (.lvm format). I need to write a correct equiliser code which is required at the receiver to correctly demodulate my signal since the channel is acoustic and would have various effects like multipath etc. The code is working without introduction of a channel. Need equiliser so that it works with the channel.