Implementation of convolutional code based on FPGA in OFDM-UWB system

Abstract

The convolutional code cell is an essential part in a transmitter of multi-band orthogonal frequency division multiplexing ultra wide band (MB-OFDM-UWB) system introduced in this paper as a kind of useful channel coding to offer more protection against all kinds of channel noise under indoor channel environments. In this paper, some kinds of convolutional codes for MB-OFDM-UWB system are designed. And then, two different structures for the implementations of convolutional codes are presented respectively. The two different structures of convolutional codes are implemented based on field programmable gate array (FPGA) chip with the software tools of ISE foundation and modelsim. The simulation results show that the performance of parallel structure is better than that of pipe line structure and that it's convenient to implement based on a mother code rate of 1/3 the punctured convolutional code with different code rates that are needed by different modules of the OFDM-UWB system. The implementation of convolutional code technique with FPGA chip can be fit to all kinds of applications of OFDM-UWB system with no transformations.