Girish Ganesan

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We consider a space-time differential modulation scheme where neither the transmitter nor the receiver has to know the channel. Our scheme is based on the theory of unitary space-time block codes. Compared to the existing differential modulation schemes for multiple antennas our scheme has a much smaller computational complexity. Moreover, our codes have a(More)
Space-Time Block Coding (STBC) requires knowledge of the channel at the receiver. In practice the channel has to be estimated. In this paper we consider three estimation/detection schemes and compare their performances. In particular we introduce a blind scheme which does not require the transmission of pilot symbols to estimate the channel.
In this paper we consider the use of differential detection when there are multiple transmitter and receiver antennas. Our differential scheme is based on the theory of Space-Time Block Codes that are used to achieve space-time diversity. Compared to the existing differential schemes for multiple antennas our scheme has a much smaller computational(More)
Orthogonal space-time block coding (OSTBC) is a recent technique that provides maximal diversity gains on a space-time channel at a very modest computational cost. Recently, several authors have suggested to improve the performance of an OSTBC system by using a feedback of channel state information from the receiver to the transmitter. In this letter, we(More)
This paper shows how the performance of orthogonal space-time block codes can be improved by using a diagonal weighting matrix at the transmitter. The optimal diagonal weighting matrix which minimizes the bit-error-rate is derived. Since the optimal weights depend on the channel, a feedback from the transmitter to the receiver is necessary. However this(More)
In this paper we consider the use of multiple antennas for wireless communication over fading channels. The fading we consider is quasi-static flat Rayleigh fading. For such a scenario optimal SNR schemes are derived when the transmitter knows the channel and when the transmitter does not know the channel. But in both cases the receiver has to estimate the(More)
A worst case lower bound (WCLB) result obtained by Nemirovskii suggests that a potentially significant estimation accuracy enhancement may be achieved provided the true parameter vector is known to belong to a ball. In this paper we discuss the many facets and implications of Nemirovskii’s result by using linear regression as a vehicle for illustration. In(More)