K. R. K. Sastry

Learn More
As demand for high quality transmission increases increase of spectrum efficiency and an improvement of error performance in wireless communication systems are important . One of the promising approaches to 4G is adaptive OFDM (AOFDM) . Fixed modulation systems uses only one type of modulation scheme (or order), so that either performance or capacity should(More)
Data rate is important in telecommunication because it is directly proportional to the cost of transmitting the signal. Saving bits is the same as saving money . In this paper we propose new digital companding scheme for OFDM system based on using different constellation orderings (QAM modulator) , depending on the data to be transmitted . Depending on the(More)
To achieve high bit rate in transmission over wireless channels frequency reuse is an encouraging concept . Rather than dividing allocated frequency spectrum into narrow band width channels , one for each user information is transmitted over a very wide frequency spectrum using the same carrier frequency within same frequency band . In this paper we propose(More)
Digital Signal Processing (DSP) has evolved as an integrated component in electronics advancement. Among all the DSP operations, Fast Fourier Transform (FFT) plays a prominent role in signal processing. FFT computational time reduces when the number of zero valued inputs (Z) outnumbers the non-zero valued inputs (NZ) due to unnecessary computations for Z.(More)
In orthogonal frequency-division multiplexing (OFDM) systems, synchronization issues are of great importance since synchronization errors might destroy the orthogonality among all subcarriers and, therefore, introduce intercarrier interference (ICI) and intersymbol interference (ISI). Several schemes of frequency offset estimation in OFDM systems have been(More)
  • 1