Redução da Complexidade do Max-Log-MPA em Sistemas SCMA

For detection in SCMA (Sparse Code Multiple Access) systems the optimal algorithm is MAP (Maximum a Posteriori). Although it has the best performance, MAP has high complexity for cases where there are a large numbers of users. Thus, the MPA (Message Passing Algorithm) has been studied as an option for detection in these systems. Even though it is smaller, MPA's complexity is also high and can be reduced. One way is to use mathematical approximations, such as is done in Max-Log-MPA. Based on this algorithm, we propose in this work a method that eliminates some calculations within the iterative part of Max-Log-MPA. This is done by comparing the values of some variables with decision thresholds.