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Bhise A.,k-Technology | Vyavahare P.D.,Sgs Institute Of Technology And Science
IET Communications | Year: 2011

Low complexity modified turbo codes (MTC) offer bit error rate performance close to Shannon's limit with significantly reduced decoding complexity. However, since interleavers used in turbo codes interleave bit positions in one-dimensional (1D) array, they cannot be used for MTC which encode information bits arranged in 2D array. Moreover, MTC use several interleavers which increase the memory requirement to store permutation patterns. Objective of this study is to design two-stage interleaver for MTC with low memory requirement, large values of column spreading factor and dispersion in the interleaved pattern. Expressions have been derived for limits on maximum values of spreading factor and dispersion for 2D information array. Simulation results show superior performance of MTC with two-stage interleavers than that with random interleavers at high bit energy to noise ratio. Moreover, analysis shows that two-stage interleaver requires 50% less memory storage than random interleaver. Proposed interleaver can also be used for turbo codes in which 1D information array is being used. © 2011 The Institution of Engineering and Technology.

Bhise A.,k-Technology | Vyavahare P.D.,Sgs Institute Of Technology And Science
IET Communications | Year: 2011

Turbo convolutional codes (TCC) are excellent error correcting codes for wireless channels. However, TCC decoders require large decoding complexity. Moreover, complexity of TCC decoder does not reduce even if puncturing is used to change the coding rate. Modified turbo codes require lower decoding complexity than TCC as they use multiple concatenations of simple block codes and convolutional codes. Recently, a class of modified turbo codes called low complexity hybrid turbo codes (LCHTC) and improved low complexity hybrid turbo codes (ILCHTC) have been proposed. It has been shown that LCHTC and ILCHTC achieve bit error rate (BER) which is comparable to TCC and have much lower decoding complexity. Simulation results show that BER performance of ILCHTC is better than that of LCHTC. Rate-1/3 ILCHTC achieve BER of 10-5 at bit energy-to-noise ratio (Eb/N0) of 1.9 dB, which is 0.4 dB higher than Eb/N0 for TCC adopted by third generation partnership project (3GPP). Moreover, ILCHTC and LCHTC decoders require half the number of computations as compared to those required for TCC decoder. In this study, union-bound analysis of ILCHTC is presented to investigate BER performance<10-6. For large interleaver lengths, analysis of theoretical union bound requires numerous computations. Therefore approximate analysis of union bound is derived from theoretical union bound. It is shown that the analysis of approximate union bound achieves reasonable accuracy. Moreover, approximate union bound can be evaluated with significantly less computational complexity than the theoretical union bound. © The Institution of Engineering and Technology.

Mishra D.K.,Sgs Institute Of Technology And Science
International Journal of Electronics | Year: 2011

In this article, the effect of pole-zero placements on settling time has been analysed for a three-stage CMOS operational amplifier (opamp) with nested Miller compensation (NMC) and reversed nested Miller compensation (RNMC) schemes. In this study, optimised balancing of speed and power is done for a three-stage CMOS opamp for a given load condition (on-chip opamp). Optimum values of circuit parameters have been derived for power efficient shifting of poles and zeros. The effect of placement of poles and zeros on dynamic settling error (DSE) is analysed by means of numerical simulation using MATLAB. This analysis will be useful to ascertain the relationship between pole-zero placements and settling time. The study of the effects of compensation elements on pole-zero placements has been done to assist the circuit designers to achieve better performance. Analysis of the effect of capacitive load on pole-zero placements and DSE has been done in this study. A technique has been developed to find out the upper and lower limits of compensation capacitor that allows fast settling with low power. The validity of the analytical work has been checked by simulation using Tanner tool in 0.35-μm CMOS technology. In the case of RNMC scheme, a power dissipation of 60.17 μw and a settling time of 340 ns are achieved; the results obtained are better than the earlier reported design technique. In the case of NMC, the simulation has been done to validate the analytical analysis. © 2011 Taylor & Francis.

Verma S.K.,Rajiv Gandhi University | Bhadauria S.S.,Sgs Institute Of Technology And Science | Akhtar S.,Rajiv Gandhi University
Frontiers of Structural and Civil Engineering | Year: 2013

Corrosion of reinforced concrete (RC) structures is one of the significant causes of deterioration of reinforced concrete (RC) structures. Chlorination is a major process governing the initiation and advancement of the injurious corrosion of steel bars. Now, several researches on the chlorination of concrete structures have been ongoing around the world. Present article reviews several recently performed chlorination studies, and from results of a field survey evaluates the effect of chloride content on the probability of corrosion and the influence of concrete compressive strength on the chloride content and penetration, also evaluates the effect of concrete cover over the chloride content of the RC structures at rebar depth and on the probability of corrosion. © Higher Education Press and Springer-Verlag Berlin Heidelberg 2013.

Gupta R.C.,P.A. College | Gupta A.K.,P.A. College | Shrivastava R.K.,Sgs Institute Of Technology And Science
Nature Environment and Pollution Technology | Year: 2013

River Kshipra is receiving a large volume of untreated sewage daily in its stretch of Ujjain city and the status of water is pathetic during low flow season. A stream water quality model QUAL-2Kw was used in the present study to simulate the contributions from different sources and sinks of dissolved oxygen and to understand the interactions among them. The model was calibrated and validated and the simulated results are in general agreement with measured water quality in River Kshipra. It was established through this study that the QUAL-2Kw model can be used for future river water quality management options for River Kshipra with reasonable accuracy.

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