Two Efficient Schemes for Providing Feedback Connection to Recursive Convolution Encoder
The IUP Journal of Electrical & Electronics Engineering, Vol. XII, No. 1, January 2019, pp. 16-31
Posted: 13 Jun 2019
Date Written: January 10, 2019
Abstract
Convolution codes are widely used error correction codes in wireless communication systems. In recursive non-systematic codes, the output of the encoder is more dependent on the previous input bits. Hence, the weight factor of the coded data increases that lead to improvement in the performance of the transmission system. The paper proposes two schemes for making the feedback connections to the recursive convolution encoder. Using these schemes, different feedback connections can be provided to the encoder for improving the performance of the system. The first scheme implements a tri-state buffer with synchronous counters in the feedback connection, and in the second scheme, a negative feedback is provided to the encoder using a NOT gate. Simulations are done using MATLAB software. The two schemes are studied using 16, 32 QAM and 16 PSK modulation schemes over AWGN channel. The results show that the first scheme leads to decrease in the Bit Error Rate (BER) as compared to conventional scheme, and the second scheme has been able to achieve the performance of conventional system.
Keywords: Error Detection and Correction (EDAC), Automatic Repeat Request (ARQ), Forward Error Correction (FEC), Non-recursive convolution codes, Recursive convolution codes
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