We investigate in this paper how to optimize the number of iterations required for sliding window decoding. The aim of this study is to reduce decoding complexity and overcome the phenomenon of decoder blocking. We propose a new design of SC-LDPC codes based on some 5G short LDPC codes to reduce decoding complexity. Simulation results demonstrate a potential reduction in decoding computational complexity of the order of 30% without significant degradation in decoding performance. In addition to taking care of complexity, this mitigates the problem of sliding window decoder blocking by reducing the probability of observing this phenomenon.