The whole globe is covered universally by water with a majority space. In
view of extraction of minerals as well as national security reasons, underwater
communication has become quite important for all the mankind. Researchers,
around the world are working for optimizing the multiple scheme in acoustic
channel. Recently, the researchers have reported valuable employability of IDMA
scheme in acoustic communication. In IDMA Scheme, the users are distinguished
with user- specific interleaving sequences based on chip-level interleaving
mechanism instead of user-specific signature sequences as engaged in CDMA
scheme. However the role regarding formation of interleavers plays vital notch
for performance of IDMA scheme in underwater communication. In this paper, the
performance of user-specific rotational interleaver has been observed in
acoustic environment for BPSK signaling scheme on MATLAB platform. Simulation
results demonstrate that the rotational interleaver performs better in terms of
bit error rate (BER) for underwater channel employing iterative IDMA system.