Projected block-wise SIC detection for communication systems with non-negativity constraints

Recently, a number of projected successive interference cancellation (PSIC) and projected parallel interference cancellation (PPIC) structures, which make use of the non-negativity constraint in incoherent OCDMA systems to enhance their performance, have been proposed and studied in (Seleem et al. in IEEE Commun Lett 16:1721–1724, 2012). Although these structures showed improved performance, they still inherit the same shortcomings of the conventional SIC/PIC structures such as large detection delay for the SIC detector and slow convergence speed for the PIC detector. In this work, we propose a new projected block-wise SIC (PBSIC) structure that not only exploits the non-negativity constraint but also overcomes the drawbacks associated with the conventional SIC/PIC structures. In particular, it largely reduces the detection delay of the PSIC detector of (Seleem et al. in IEEE Commun Lett 16:1721–1724, 2012), while it enjoys the same fast convergence speed. Two approaches for decreasing the computational complexity of the proposed detector are investigated. Simulation results are in total agreement with our theoretical findings.