  Sequences having better autocorrelation properties play a crucial role in
enhancing the performance of active sensing systems. Hence, sequences with good
autocorrelation properties are very much in demand. In this paper, we addressed
the problem of designing a unimodular sequence having better side-lobe levels.
We formulated it as a constrained optimization problem comprising the
Integrated Side-lobe Level (ISL) metric and then proposed an effective
algorithm (named UNIPOL - UNImodular sequence design via a separable iterative
POLynomial optimization) where we perform the polynomial optimization at every
iteration. The novelty of the paper comes from deriving a quartic majorization
function that is separable in the sequence variables and that can be minimized
parallelly. To evaluate the performance of our proposed algorithm we perform
the numerical experiments for different sequence lengths and confirm that our
proposed algorithm is the fastest algorithm to attain an actual optimum
minimizer of the ISL metric. Our proposed algorithm is also computationally
efficient due to its ease of implementation using the FFT, IFFT operations in a
parallel fashion.
