Muhammad Danish Nisar

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Relaying is undoubtedly a key technology for future wireless networks as it can be applied to provide coverage extension and capacity increase in a cost-effective manner. This paper presents an outline of the major advanced relaying concepts that will be part of future systems from the viewpoint of the ARTIST4G European project. These concepts can be(More)
Inherent inter-symbol and inter-carrier interference elimination ability of cyclic prefixed OFDM transmission fails for the case of multipath fading channels when the Channel Impulse Response (CIR) length exceeds the duration of Cyclic Prefix (CP). Conventional channel estimation and equalization schemes, if applied to this case of insufficient CP, suffer(More)
It has been shown that adaptive power allocation can provide a substantial performance gain in wireless communication systems when perfect channel state information (CSI) is available at the transmitter. However when only imperfect CSI is available, the performance may degrade significantly, and as such robust power allocation schemes have been developed to(More)
An a priori information aware channel equalizer accepts some prior information about the unknown transmit symbols, in addition to the knowledge of channel coefficients and noise covariance, and therefore offers a superior performance as compared to an equalizer that lacks this additional information. Such an equalizer is employed, for instance, in turbo(More)
Pilot-aided channel estimation for multi-carrier systems can be significantly improved by exploiting time and frequency correlations between the channel frequency response coefficients. But in practice, the knowledge of channel correlation function is not accurately available, thereby necessitating the need of an estimator that employs a fixed correlation(More)
Adapting the transmission strategy under partial or uncertain channel state information (CSI) at the transmitter is of importance in practical systems with imperfect channel knowledge. In this work, we consider the problem of power allocation in a system of parallel communication sub-channels with uncertain CSI. We adopt the robust (minimax) optimization(More)