Efficient mapping on FPGA of a Viterbi decoder for wireless LANs

Abstract

In this paper an optimized hardware implementation on FPGA of a Viterbi decoder is presented for WLAN. A fixed-point analysis is made and its performance is compared with a soft decision decoding floating point model with CSI weight. Only 6 bits are needed to perform the soft quantification and 7 bits to the CSI, in order to maintain the performance of the floating point model. A normalization method is proposed to increase the throughput of the decoder, being possible to decode 172 Mbps when it is implemented in a Virtex 2 device. Power consumption results of the decoder implementation are presented for Hiperlan/2 maximum rate. Moreover, it has been shown that it is possible to reduce the power consumption disabling the unnecessary hardware depending on the WLAN modes.