Ramachandran Ramanathan

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—The increment in the sizes of the images by the technological advances accompanies high demand for large capacities, high performance devices, high bandwidths etc. Therefore, image compression techniques are essential to reduce the computational or transmittal costs. Wavelet transform is one of the compression techniques especially used for images and(More)
In this paper, we investigate the performance of the low-complexity algorithms based on Likelihood Ascent Search (LAS) and Tabu Search (TS) for detection in MIMO systems with channel estimation errors. Here, we briefly review the algorithms for LAS and TS and their variants and subsequently compare them for various MIMO settings. We provide the simulation(More)
This paper proposes a new approach to real time economic and emission dispatch by using orthogonal least-squares (OLS) and modified particle swarm optimization (MPSO) algorithms to construct the radial basis function (RBF) network. The objectives considered are fuel cost and NOx/CO2 emissions. The RBF network is composed of input, hidden, and output layers.(More)
In this paper, we propose a hybridized Likelihood Ascent-Mixed Gibbs Sampling (LAS-MGS) for effective detection with channel estimation error. We analyze its performance in the presence of channel estimation error for 2×2 and 4×4 MIMO systems employing BPSK modulation scheme. At low SNRs, performance of ZF-MGS and LAS-MGS is similar but at(More)
In this paper, we propose an approach based on Lattice Reduction (LR) algorithm which preserves the channel norm in the presence of estimation errors. We analyze the channel norm of perfect and imperfect channel by employing LR algorithm on both perfect and imperfect channels in MIMO systems with 2, 4, 8 and 16 antennas for various error variances. We(More)
With congested wireless spectrum and increasing number of users, cognitive radio serve as a panacea for efficient spectrum utilization. This stands to substantiate the amount of research happening in this area. Spectrum sensing is indubitably a key functionality in cognitive radio, which helps determining the spectral holes and white spaces for the(More)
Wireless communication is an emerging and evergreen field of research and will continue to be so in the future. Increased demands in spectrum and users eventually result in spectral congestion. Cognitive Radio systems provide an intelligent and an attractive solution to this problem. Spectrum Sensing is the main key for the functioning of Cognitive Radio(More)
The MIMO system convincingly promises a better bit rate in comparison with a SISO system. The system gets even efficient when OFDM is implemented with MIMO to obtain better data rates even in hostile channel environment. Research establishes OFDM as a potential candidate for use in MIMO systems for the reasons like inherent FFT, waveform adaptation,(More)