Prasad Shamain

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AbstractSpace-time block codes (STBC) have been proposed as a less complex alternative to space-time trellis codes for achieving transmit diversity. Application of such STBCs to code division multiple access (CDMA) systems is called space-time spreading (STS). STS schemes have been considered under the assumption of independent transmit fades and ideal(More)
It has been shown that employing a higher order constellation in conjunction with CDMA can improve the performance of the multiuser system in severe multipath channels. We verify that the performance improvement gained by the above interference suppression technique in the multiuser case continues to hold in the multiuser environment with narrowband(More)
In this paper, we study the baseband estimation of the frequency- dependent imbalance between the in-phase and quadrature branches (I/Q imbalance) of a direct-conversion receiver, by exploiting the preambles which is not specially designed for I/Q imbalance estimation. We propose an in-service estimation method which consists of two stages: the first stage(More)
Multicarrier (MC) code division multiple access (CDMA) is an attractive way of implementing wideband CDMA systems while being backwardcompatible with the existing narrowband CDMA systems. Initial acquisition in MC-CDMA has been studied for the case where the subcarriers experience independent fades. For many of scenarios, the assumption about the(More)
Antenna diversity is an effective way of improving performance of a communication system, especially for initial acquisition in a narrowband code division multiple access (CDMA) system that operates in a flat fading environment. Earlier attempts to analyze such systems assume independent fading at various antenna elements. However, the diversity gain(More)
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