iosr-JECE   Volume-7 ~ Issue-6

Abstract: In this paper we have designed and implemented(15, k) a BCH Encoder on FPGA using VHDL for reliable data transfers in AWGN channel with multiple error correction control. The digital logic implementation of binary encoding of multiple error correcting BCH code (15, k) of length n=15 over GF (24) with irreducible primitive polynomial x4+x+1 is organized into shift register circuits. Using the cyclic codes, the reminder b(x) can be obtained in a linear (15-k) stage shift register with feedback connections corresponding to the coefficients of the generated polynomial. Three encoder are designed using VHDL to encode the single, double and triple error correcting BCH code (15, k) corresponding to the coefficient of generated polynomial. Information bit is transmitted in unchanged form up to k clock cycles and during this period parity bits are calculated in the LFSR then the parity bits are transmitted from k+1 to 15 clock cycles. Total 15-k numbers of parity bits with k information bits are transmitted in 15 code word. Here we have implemented (15, 5, 3), (15, 7, 2) and (15, 11, 1) BCH code encoder on Xilinx Spartan 3 FPGA using VHDL and the simulation & synthesis are done using Xilinx ISE 13.3. BCH encoders are conventionally implemented by linear feedback shift register architecture. Encoders of long BCH codes may suffer from the effect of large fan out, which may reduce the achievable clock speed. The data rate requirement of optical applications require parallel implementations of the BCH encoders. Also a comparative performance based on synthesis & simulation on FPGA is presented.

Keywords: BCH, BCH Encoder, FPGA, VHDL, Error Correction, AWGN, LFSR cyclic redundancy checking, fan out .

[1]. M.Y. Rhee - "Error Correcting Coding Theory", McGraw-Hill, Singapore, 1989.
[2]. S. Lin, and D.J. Costello Jr. - "Error Control Coding", Prentice-Hall, New Jersey, 1983.
[3]. E. R. Berlekamp, "Algebraic coding theory", McGraw-Hill, New York, 1968.
[4]. R.E. Blahut, "Theory and practice of error-control codes", Addison-Wesley, Reading, MA, 1983
[5]. S. B. Wicker, Error Control Systems for Digital Communication andStorage. Upper Saddle River, New Jersey 075458: Prentice Hall, Inc,1995.
[6]. J. H. Derby, "High-speed CRC computation using state-space transformation" in Proc. Global Telecommunications Conf. 2001, GLOBECOM.
[7]. R. J. Glaise, "A two-step computation of cyclic redundancy code CRC-32 for ATM networks," IBM J. Res. Dev., vol. 41, pp. 705–709
[8]. K. K. Parhi, VLSI Digital Signal Processing Systems-Design and Imple mentation. New York: Wiley, 1999.
[9]. Goresky, M. and Klapper, A.M. Fibonacci and Galois representations of feedback-with-carry shift registers, IEEE Transactions on Information Theory, Nov 2002, Volume: 48, On page(s): 2826 –2836.
[10]. Panda Amit K, Rajput P, Shukla B, "Design of Multi Bit LFSRPNRG and Performance comparison on FPGA using VHDL", International Journal of Advances in Engineering & Technology (IJAET), Mar 2012, Vol. 3, Issue 1, pp. 566-571

Abstract: Ultra Wideband (UWB) is an inherent technology used in current wired and wireless communication systems. These systems share the radio frequency spectrum with narrowband signals and also provide high data rates, low cost, greater bandwidth, good time domain resolution and improved channel capacity. UWB technology has attracted a lot of inquisitiveness in researchers worldwide. There are several challenges in designing a UWB receiver such as channel estimation and interference mitigation. In multi-user environments, multiple access interference (MAI) degrades the performance of UWB systems. To prevail over these challenging issues, an adaptive and robust receiver needs to be designed to alleviate interference in all types of environments. In this paper, the different types of receiver structures like Rake, energy, correlation, suboptimal, near-optimal and adaptive nonlinear rake receivers are surveyed and their performances are analyzed. This survey helps to realize superior bit error rates (BER) and excellent signal-to-noise ratios (SNR).

Keywords: Adaptive nonlinear rake receivers, Correlation receivers, Energy detectors, Rake receivers, Ultra wideband (UWB).

[1] Ian Oppermann, Matti Hamala Inen and Jari Iinatti., UWB theory and Applications (Wiley, 2004).
[2] R. Malhotra, "UWB Communication Receiver: Review and Design Considerations", Int. J. of Advanced Engineering Sciences and Technologies, vol. No. 8, no. 2,197 – 202.
[3] D. Cassioli, M.Z. Win, F. Vatalaro, A.F. Molisch, "Low Complexity Rake Receivers in Ultra-Wideband Channels", IEEE Trans. Wireless Comm. ,vol. 6, no.4, April 2007.
[4] Rashid A. Fayadh, F. Malek, Hilal A. Fadhil, N. A. Mohd Affendi, Azuwa Ali and M. F. Haji Abd Malek "Adaptive Rake Receiver Using Matched Filter with Three Combining Techniques", Australian J. of Basic and Applied Sciences, 7(5), 26-33, 2013.
[5] Mustafa E. S¸ Ahin and Huseyin Arslan "Inter-symbol Interference in High Data Rate UWB Communications Using Energy Detector Receivers", Research by Honeywell, Inc. and Custom manufacturing & Engineering, Inc.
[6] Tomaso Erseghe and Stefano Tomasin "Optimized Demodulation for MAI Resilient UWB W-PAN Receivers ", IEEE 2008.
[7] Fredrik Tufvesson, Sinan Gezici, and Andreas F. Molisch "Ultra-Wide band Communications using Hybrid Matched Filter Correlation Receivers", IEEE Trans. Wireless Comm.., vol. 5, no. 11, Nov. 2006.
[8] Tsung-Hui Chang, Chong-Yung Chi and Yu-Jung Chang "Space–Time Selective RAKE Receiver With Finger Selection Strategies for UWB Overlay Communications", IEEE Transactions on Microwave theory and techniques, vol. 54, no. 4, April 2006.
[9] Dong In Kim "Near-optimal and Suboptimal Receivers for Multiuser UWB Impulse Radio Systems in Multipath", IEEE Trans. Comm., vol. 57, no.11, November 2009.
[10] S. Niranjayan and N.C. Beaulieu "Novel Adaptive Nonlinear Receivers for UWB Multiple Access Communications", IEEE Trans. Wireless Comm.., vol. 12, no.5, May 2013.

Abstract: In this paper we proposed corrugated SIW horn antenna (CSIW). CSIW technology does not require conducting vias to achieve TE10 type boundary conditions. Here vias are replaced by quarter wavelength microstrip stubs arranged in a corrugated pattern on the edges of the waveguide. We have implemented CSIW technology to design horn antenna, so that CSIW horn antenna will have inherited advantage of conventional horn antenna like low VSWR, High gain, relatively wide bandwidth. For the purpose of simulation HFSS is used. Simulation result for CSIW horn antenna in X band is presented here. The objective of this paper is to provide broad perspective of CSIW horn antenna. CSIW horn antenna provides high gain and directivity with wide bandwidth.

Keywords : Substrate Integrated Waveguide (SIW), vias, corrugated Substrate Integrated Waveguide (CSIW), Microstrip stubs.

[1] J. Hirokawa and M. Ando, "Single-layer feed waveguide consisting of posts for plane TEM wave excitation in parallel plates," IEEE Trans. Microwave Theory & Tech., vol. 46, no. 5, pp. 625-630, May 1998.

[2] D. Deslandes and K. Wu, "Accurate modeling, wave mechanism, and design consideration of a substrate integrated waveguide," IEEE Trans. Microwave Theory & Tech., vol. 54, no. 6,pp. 2516-2526, Jun. 2006.

[3] D. G. Chen and K. W. Eccleston, ―Substrate integrated waveguide with corrugated wall,‖ in Proc. Asia–Pacific Microw. Conf., 2008.