Muhammad Danish Nisar

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DFT Spread OFDM has been proposed recently to reduce the Peak to Average Power Ratio (PAPR) of conventional OFDM transmission. Besides PAPR reduction, an important implication of DFT Spreading is that the independent parallel sub-channels between the sub-carriers cease to exist. This in turn leads to difference in its performance limits as compared to the(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)
— 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)
Co-Channel Interference (CCI) is one of the major bottlenecks in the performance of today's densely planned wireless cellular systems. A receiver equipped with multiple receive antennas and sufficient computational budget typically exploits the spatial dimension and iterative processing between the detector and the channel decoder to suppress this(More)
In this work, we investigate the issue of interference coordination in relay-enhanced networks. We focus on Type 1 in-band relays as proposed for LTE-Advanced, where the base station and the relay nodes share the same frequency for the backhaul and relay access link. While using full-buffer traffic for the downstream, we propose a centralized interference(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)
The paper extends the recently proposed concept of finite dimensional robust 2-D MMSE channel estimation to the staggered pilot grids in multi-carrier systems. The proposed scheme is particularly useful once the receiver has no knowledge of the channel correlation function and it intends to pursue the MMSE channel estimation for improved performance. We(More)
Some of the key driving forces behind the transition from the UMTS based cellular system to the Long Term Evolution Advanced (LTE-A) are to improve the mean and the cell-edge throughput, improve the user fairness, and improve the quality of service (QoS) satisfaction for all users. In the latter system, relays appear as one of the most prominent enabler for(More)