A REDUCED MEMORY MAP ALGORITHM FOR TURBO CODES

Abstract. In this paper, a new method to reduce up to 90 % of the memory necessary (for a four memory code) implied in MAP algorithms (also, LogMAP and MaxLogMAP algorithms) is presented. The proposed solution is to recalculate the backward coefficients in the same direction as the forward coefficients. Even if the volume of the calculation increases with the appearance of an additional recurrence, the decoding time can be reduced by the elimination of some times of the memory access