Neelesh B. Mehta

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A simple, novel, and general method is presented in this paper for approximating the sum of independent or arbitrarily correlated lognormal random variables (RV) by a single lognormal RV. The method is also shown to be applicable for approximating the sum of lognormal-Rice and Suzuki RVs by a single lognormal RV. A sum consisting of a mixture of the above(More)
Cooperative transmission by base stations (BSs) can significantly improve the spectral efficiency of multiuser, multicell, multiple input multiple output (MIMO) systems. We show that contrary to what is often assumed in the literature, the multiuser interference in such systems is fundamentally asynchronous. Intuitively, perfect timing-advance mechanisms(More)
The use of energy harvesting (EH) nodes as cooperative relays is a promising and emerging solution in wireless systems such as wireless sensor networks. It harnesses the spatial diversity of a multi-relay network and addresses the vexing problem of a relay’s batteries getting drained in forwarding information to the destination. We consider a cooperative(More)
Cooperative communications, where parallel relays forward information to a destination node, can greatly improve the energy efficiency and latency in ad-hoc networks. However, current networks do not fully exploit its potential, as they only use traditional energy-accumulation, which is often used in conjunction with repetition coding or cooperative(More)
We consider a cooperative wireless network where the source broadcasts data to relays, some or all of which cooperatively beamform to forward the data to the destination. The network is subject to an overall outage constraint. We generalize the standard approaches for cooperative communications in two respects: (i) we explicitly model and factor in the cost(More)
Frequency-domain scheduling and rate adaptation enable next generation orthogonal frequency division multiple access (OFDMA) cellular systems such as Long Term Evolution (LTE) to achieve significantly higher spectral efficiencies. LTE uses a pragmatic combination of several techniques to reduce the channel state feedback required by a frequency-domain(More)
We introduce two novel joint radio-frequency (RF)-baseband designs for receivers in a MIMO system with Nt transmit antennas, Nr receive antennas, but only L ¡ Nr RF chains at the receiver. The joint design introduces an RF pre-processing matrix that processes the signals from the different antennas, and is followed by selection (if necessary),(More)
We develop an alternate characterization of the statistical distribution of the inter-cell interference power observed in the uplink of CDMA systems. We show that the lognormal distribution better matches the cumulative distribution and complementary cumulative distribution functions of the uplink interference than the conventionally assumed Gaussian(More)