A Novel High Speed and Area-Efficient Of Hybrid Turbo Decoders

Abstract

Long Term Evaluation (LTE) has been used to achieve peak data rates in wireless communication system. Turbo codes are used as the channel encoding scheme. multiple maximum a posteriori (MAP) algorithm has been used as a decoding scheme. Complexity in MAP algorithm is reduced by implementing the algorithm in log domain giving rise to Log MAP algorithm. The main objective of this work is to reduce the complexity of state metric computation by employing of various algorithms and these algorithms differ only by their implementation of correction terms.  The state metric calculation is implemented with the help of radix-4 Add -Compare-Select (ACS) unit. The distance calculation involved between two concurrent computations of state metric can be shared among them which give rise to Maximum Shared Resource (MSR) architecture. The proposed implementation of these algorithms leads to reduction in the power dissipation, propagation delay and the number of logical elements used for the recursion computation in turbo decoders used in LTE system.