Balachander Narasimhan

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— Effective Inter-carrier Interference (ICI) mitigation for MIMO-OFDM requires accurate channel estimation which is very challenging due to the large number and fast time-varying nature of the channel parameters to be estimated using scattered pilots. We present a novel SFBC-OFDM scheme for doubly-selective channels and a reduced-complexity channel(More)
Direct conversion orthogonal frequency division multiplexing (OFDM) systems suffer from transmit and receive analog processing impairments such as in-phase/quadrature (I/Q) imbalance causing inter-carrier interference (ICI) among sub-carriers. Another source of performance-limiting ICI in OFDM systems is Doppler spread due to mobility. However, the nature(More)
—Direct-conversion multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) transceivers enjoy high data rates and reliability at practical implementation complexity. However, analog front-end impairments such as I/Q imbalance and high mobility requirements of next-generation broadband wireless standards result in(More)
Dissolution-controlled drug delivery systems are characterized by a phase erosion of the polymer carrier that is associated with fast or slow dissolution of the macromolecular chains. The molecular nature of the dissolution phenomenon was examined by analyzing the water transport process and the subsequent polymer chain disentanglement that is usually(More)
Effective inter-carrier interference (ICI) mitigation for MIMO-OFDM requires accurate channel estimation which is very challenging due to the large number and fast time-varying nature of the channel parameters to be estimated using scattered pilots. We present a novel SFBC-OFDM scheme for doubly-selective channels and a reduced complexity channel estimation(More)
I/Q imbalance and high mobility in OFDM systems result in performance-limiting intercarrier interference (ICI). However, the nature of ICI due to each of them is quite different. Unlike previous works which considered these two impairments separately, we develop a unified mathematical framework to characterize and mitigate ICI when both impairments are(More)
Direct-conversion Orthogonal Frequency Division Multiplexing (OFDM) systems suffer from transmit and receive analog processing impairments such as In-phase/ Quadrature (I/Q) imbalance causing Inter-Carrier Interference (ICI) between the sub-carriers. Another source of performance-limiting ICI, but with a different nature, in OFDM systems is Doppler spread(More)
Previous work [1] on I/Q imbalance in SC-FDE transceivers investigates the effect of receiver I/Q imbalance but does not consider Doppler effects due to mobility. SCFDE in doubly-selective channels is studied in [2] and [3] but without considering I/Q imbalance. In this paper, we derive an equivalent channel model for SC-FDE in the presence of both joint(More)
In our previous work [1], digital baseband compensation of joint Tx/Rx I/Q imbalance in mobile SC-FDE transceivers was investigated. In this sequel, the training sequence design for joint channel and I/Q imbalance parameter estimation in mobile SC-FDE transceivers is discussed in greater detail.