Umar Rizvi

In this paper, we investigate the robustness of the 60 GHz connectivity in typical indoor environments by analyzing the outage probability. We define three realistic indoor scenarios which may host the 60 GHz networks in the future and perform simulations with a verified 3D ray tracing tool on them. In the first set of simulations, we show the impact of

Over the last couple of decades, wireless communication has proved to be a phenomenal success and has generated a booming industry with over 5 billion mobile handsets in use worldwide. This has on one end eased the life of its users while on the other end has introduced new challenges for wireless system designers. The varying nature of the wireless communication channel results in large differences in the instantaneous received signal strength. Since most mobile terminals are battery powered and operate in a network, simply increasing the transmission power is not an attractive solution, as it reduces the battery life and increases interference. Thus a major challenge in wireless communication is to increase the communication rate and link reliability by utilizing low power, low cost and spectrally efficient systems. Even with the advent of efficient signal processing techniques and miniaturized low power signal processing hardware, the physical bottleneck still remains the availab...

Rotation of the signal constellation together with in-phase and quadrature channel interleaving (signal space diversity) is known to provide good performance gains over fading channels for multi level modulation methods. This paper studies the extension of such schemes with a low density parity check (LDPC) code. It is shown that for both coded and un-coded Gray-mapped MPSK modulation formats with

In this paper we propose modulation diversity as a candidate diversity scheme for uncoded cooperative communication in wireless networks with decode-and-forward (DF) communication protocol. A performance analysis of such a scheme in Nakagami-m fading channels in the presence of additive white Gaussian noise (AWGN) is presented. An upper bound on the average probability of bit error (Pb) and average probability

ABSTRACT The main target of a 60 GHz transceiver system is to obtain data rates close to gigabits per second (Gbps) over short distances. The 60 GHz band suffers from severe pathloss, inter-symbol interference (ISI) and a limited link budget. In order to improve the link budget, beamforming techniques are utilized. Antenna beamforming, i.e., combining signals from multiple receive antennas is one of the crucial aspects of the 60 GHz transceiver system. Adaptive antenna arrays are considered for the beamforming. A single carrier with frequency domain equalization (SC-FDE) is used for the modulation. In order to suppress the ISI, a cyclic prefix (CP) is used in SC-FDE. The effects of the physical parameters of antenna arrays on the RMS delay spread and BER have been investigated in LOS/NLOS condition. An algorithm for radio frequency (RF) level beamforming is proposed. The effects of perfect channel and non-perfect channel on the BER have been investigated using the proposed beamforming algorithm. The effects of the antenna array physical parameters on the BER using the proposed beamforming algorithm have also been investigated. It was seen that the BER improves after the implementation of the new beamforming algorithm. The 60 GHz band shows severe ISI which is improved by using the proposed beamforming algorithm.

The use of a unique bit-to-symbol mapping for each diversity branch (often referred to as constellation rearrangement) is known to provide good perfor- mance for higher level linear modulation techniques when used in conjunction with orthogonal transmit diversity (OTD) and automatic repeat request (ARQ) schemes. This paper investigates the performance of constellation rearrangement scheme when used in conjunction with multiple

Professor : Prof. Dr. ir. Ignas Niemegeers (WMC-TU Delft) Supervisor : Dr. ir. Gerard Janssen (WMC-TU Delft) Mentor : Umar Hassan Rizvi (WMC-TU Delft) External Examiner : Dr. ir. Geert Leus (Circuits and Systems) ... Wireless and Mobile Communications (WMC) Faculty of ...

The use of a unique bit-to-symbol mapping for each diversity branch (often referred to as constellation rearrangement) is known to provide good performance for higher level linear modulation techniques when used in conjunction with orthogonal transmit diversity (OTD) and automatic repeat request (ARQ) schemes. This paper investigates the performance of constellation rearrangement scheme when used in conjunction with multiple transmit antennas and space time block codes. A modified space-time block coding ...