Study Of Viterbi Decoder Used In 802.11 Transceivers

Communication with flexible and efficient approach is always a nice desire. Especially, with the improvement of digital communication technology, people demand more reliable and more efficient information transmission in recent years. There are tow approaches to meet the requirements: one is enhancing the SNR; the other one is adopting encoding technique. With the development of encoding theory and the VLSI technique, encoding equipment is more simply and cheaper. Therefore, error correcting technique is used widely. The Convolutional encoder and the Viterbi decoder is an efficient forward error correcting method, which is widely used in satellite communication and mobile communication.This paper mainly studied a Viterbi decoder, which is used in WLAN transceiver on the protocol 802.11. The key of the design of the Viterbi decoder is searching for an optimal architecture, which can both meet the requirement of bit error rate and reduce the power. According to the factors above, the Viterbi decoder adopted soft decision mode to reduce bit error rate, chose the radix-2 module to reduce the complexity, adopted trace back architecture to save power.This paper proposed a special dynamic configurable trace back depth Viterbi decoder, which can dynamically configure trace back depth, based on the architecture above and the protocol 802.11. The improved architecture can save more power, in the case of a low encoding rate.At last, this paper settled the simulation environment on MATLAB, and proved the improvement available by MATLAB simulation. At the same time, this paper verified the BER of the WLAN transceiver by MATLAB simulation.