Integrated implementation of fixed-point turbo decoders for LTE system

In this paper, we discussed the fixed-point implementation of LTE turbo decoder with Max-Log-MAP algorithm. We focused on the non-uniform quantization scheme of received information. In addition, modular arithmetic was introduced to the state metric calculation, as well as the "Scale" process to extrinsic information calculation. With small hardware implementation complexity, the resource overhead is reduced, and the working speed is improved. Furthermore, simulation results show that, using this proposed fixed-point implementation scheme, the decoding performance is much better than traditional Max-Log-MAP and closed to the Log-MAP algorithm, with a minor degradation less than 0.1 dB.