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In wide communication network, signals are transferred and receive. In case of wireless systems transferring a signal over a wide spectrum and providing a security to such signal is a tough task. While transferring a signal extra security is needed to hide the original message signal, to provide such security Pseudo Noise sequence is used. PN sequence uses linear feedback shift register (LFSR). A Vedic multiplier is an ancient method of mathematics using Vedic sutras. Uradhava triyakabham (vertically and crosswise) is one of the sutra used for design of fast and efficient multiplication. VHDL simulation of Vedic multiplier is done.

For binary field and long code lengths, Low Density Parity Check (LDPC) code approaches Shannon limit performance. LDPC codes provide remarkable error correction performance and therefore enlarge the design space for communication systems.In this paper, we have compare different digital modulation techniques and found that BPSK modulation technique is better than other modulation techniques in terms of BER. It also gives error performance of LDPC decoder over AWGN channel using Min-Sum algorithm. VLSI Architecture is proposed which uses the value re-use property of min-sum algorithm and gives high throughput. The proposed work has been implemented and tested on Xilinx Virtex 5 FPGA. The MATLAB result of LDPC decoder for low bit error rate (BER) gives bit error rate in the range of 10-1 to 10-3.5 at SNR=1 to 2 for 20 no of iterations. So it gives good bit error rate performance. The latency of the parallel design of LDPC decoder has also reduced. It has accomplished 141.22 MHz maximum frequency and throughput of 2.02 Gbps while consuming less area of the design.