Implementation of turbo code with early iteration termination in GNU radio

Wireless communication systems demand energy efficient and performance optimized error correction scheme. Turbo code, an iterative error correction code, shows strong error correction capability. Many wireless communication systems use Turbo code in their standards due to its near ideal performance. The iterative nature of Turbo decoder introduces additional computations, decoding delay, and power consumption. The number of iterations required to obtain the desired output varies with the channel conditions. Early iteration termination at appropriate time reduces the computational complexity without performance degradation. An early iteration termination based on the absolute value of the mean of extrinsic information has been proposed recently. This technique efficiently terminates the iteration at low and high SNR conditions and also minimizes the half iterations. Software Defined Radio (SDR), a communication system technology, is a common platform that supports various standards. GNU Radio is the software part of SDR that allows implementing various features of communication systems. A low complex Turbo decoder in GNU Radio along with Universal Software Radio Peripheral (USRP) helps to implement real time applications with low decoding delay and reduced complexity. In this paper, Turbo CODEC with early iteration termination has been implemented in GNU Radio platform