MIMO-OFDM systems with pre-filtering as well as bit and power loading have gained a lot of interest recently. These systems are based on theoretically optimal solutions maximizing the uncoded throughput and constraining the maximum uncoded BER. In this paper, we extend the existing frameworks to coded systems with bit and packet error ratio adaptation. We evaluate the performance of this approa...

In this paper, we propose an algorithm called Optimum Intensity Based Distributed Hiding (OIBDH) for secret data hiding inside cover images. The algorithm is a modified version of Bit Plane Splicing LSB technique with better hidden capacity and improved embedding process. The proposed algorithm outperforms Bit Plane Splicing LSB technique as more data can be hidden without degrading the quality...

In this paper, we address the problem of deriving bit-wise metrics for the Viterbi decoding of a bitinterleaved coded modulation. We put an emphasis on Gray-mapped high order QAM constellations, and illustrate the performance in the context of the IEEE 802.11a/g wireless OFDM system. Several bit metric formulas are compared, enabling a performance versus complexity trade-off. It is shown that n...

Abstract—Approximations to the union bound performance of sequence detection in the presence of colored noise and an algorithm to compute bit error and error event probabilities are presented and compared to bitby-bit simulation results. These computations, which are very accurate at bit error probabilities , are then used to analyze the performance of standard and reverse concatenated Reed-Sol...

This paper devotes itself to the study of secret message delivery using cover image and introduces a novel steganographic technique based on genetic algorithm to find a near-optimum structure for the pair-wise least-significant-bit (LSB) matching scheme. A survey of the related literatures shows that the LSB matching method developed by Mielikainen, employs a binary function to reduce the numbe...

In the course of the evaluation of the stream cipher SOBER-t32 submitted to NESSIE, a correlation between initial states has been found for related keys. With high probability some sums of bits of the initial state after key loading do not change their value when a bit of the key is inverted. This holds also for the loading of frame keys. It is shown that the required condition for the frame ke...

We investigate the energy optimization (minimization) for amplified links. We show that using the using a well-established analytic nonlinear signal-to-noise ratio noise model that for a simple amplifier model there are very clear, fiber independent, amplifier gains which minimize the total energy requirement. With a generalized amplifier model we establish the spacing for the optimum power per...

The paper deals with analysis of loading conditions on damping torque coefficient and synchronizing coefficient in SMIB system and design of Delta-Omega type of damping controller for damping of power oscillations in the system. Effect of variation of loading on synchronizing torque and damping torque coefficients has been investigated in detail. A new design approach for optimizing the paramet...