Analysis of iteration control for turbo decoders in turbo synchronization applications

摘要

Wireless data transmission results in frequency and phase offsets of thesignal in the receiver. In addition, the received symbols are corrupted bynoise. Therefore, synchronization and channel coding are vital parts of eachreceiver in digital communication systems. By combining the phase andfrequency synchronization with an advanced iterative channel decoder (innerloop) e.g. turbo codes in an iterative way (outer loop), the communicationsperformance can be further increased. This principle is referred to as turbosynchronization. The energy consumption and the peak throughput of the systemdepend on the number of iterations for both loops. An advanced iterationcontrol can decrease the mean number of needed iterations by detectingcorrectly decoded blocks. This leads to a dramatic energy saving or to anincrease of throughput. In this paper we present a new stopping criterion fordecodable blocks for turbo decoding in interrelation with turbosynchronization. Furthermore the implementation complexity of the turbodecoder is shown on a Xilinx FPGA.