Experimental investigation of punctured convolutional codes for real time embedded systems in indoor wireless channels.

摘要

Channel coding schemes, ubiquitous in wireless standards, provide robust data transmission without the need for retransmission. Punctured convolutional coding is one of the mechanisms to enable variable bit-rate communication, thus enabling data transmission at optimum rate. It also reduces decoding complexities associated with implementation of high rate convolutional codes. With the increase in penetration of indoor wireless networks, there has been widespread interest in evaluating the performance of various systems in such indoor channels.; The main aim of this thesis work was to evaluate performance of punctured convolutional codes in indoor point-to-point wireless data transmission systems for channels characterized by slow fading Rician with and without Line of Sight (LOS). The effect of traceback length of Viterbi decoder on the performance of the system is also evaluated. It is noted that coding gain increases by approximately 1.5 db with the use of traceback length of Viterbi decoder equal to length of input stream. It is found that coding gain decreases gradually with increase in puncturing of data, thus enabling a smooth trade-off between error-performance and data rate. Coding loss of approximately 1 dB is noted with increase in channel rate by 33%.