A Comparative Study of IEEE 802.11p Physical Layer Coding Schemes and FPGA Implementation for Inter Vehicle Communications

This paper provides a comprehensive investigation of the performance and practical implementation issues of two coding schemes, employing Concatenated Reed Solomon Codes with Convolutional Codes and Turbo Codes, over vehicular ad-hoc networks based on the IEEE 802.11p specifications. In this article we present the results of an evaluation of system performance using simulation for the two different coding schemes. We concentrate our evaluation on different propagation conditions (Additive white Gaussian noise?AWGN, Ricean Fading and Rayleigh Fading). BER (Bit Error Rate) and SNR (Signal to Noise Ratio) for different data rates are examined and tested. The Turbo coding scheme achieves significant performance improvements compared to the other technique. The Forward Error Correction (FEC) system model in the transmitter and the receiver with the two schemes has been implemented in a Field Programmable Gate Array (FPGA) from Xilinx using the System Generator tool-flow for fast prototyping. At the end, a test-bed was developed using the Nallatech XtremeDsp Development Kit with a Xilinx Virtex-4 FPGA, for comparing simulation results with real time implementations. The overall conclusion of this paper is that Turbo Codes offer considerably improved performance with low hardware complexity to the 802.11p standard, directly applicable to the Intelligent Transport System (ITS) domain.