Seyran Khademi

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A peak to average power ratio (PAPR) reduction method is proposed that exploits the precoding or beamforming mode in WiMAX. The method is applicable to any OFDM/A systems that implements beamforming using dedicated pilots which use the same beamforming antenna weights for both pilots and data. Beamforming performance depends on the relative phase shift(More)
The paper develops a new technique to reduce the peak to average power ratio (PAPR) in OFDM modulation for a MIMO system. The proposed method exploits the eigen-beamforming mode (EM) in MIMO systems which is a common feature in 4th generation standards: WiMAX and LTE. These systems use the same beamforming weights for dedicated pilots and data so the(More)
A new peak-to-average power ratio (PAPR) reduction approach for MIMO-OFDM/A is developed based on the well-known constant modulus algorithm (CMA). This combines two ideas: 1) time domain signals from “resource blocks” (consisting of several subcarriers) may be linearly combined using precoding weights, transparent to the receiver; 2) the(More)
The processing required for the global maximization of the intelligibility of speech acquired by multiple microphones and rendered by a single loudspeaker, is considered in this paper. The intelligibility is quantized, based on the mutual information rate between the message spoken by the talker and the message as interpreted by the listener. We prove that(More)
Speech intelligibility enhancement is considered for multiple-microphone acquisition and single loudspeaker rendering. This is based on the mutual information measured between the message spoken at far-end environment and the message perceived by a listener at near-end. We prove that the joint optimal processing can be decomposed into far-end and near-end(More)
In this paper, we jointly solve the problem of transmit antenna selection and zero-forcing (ZF) precoding in a multiple input multiple output (MIMO) system. A new problem formulation is proposed which enables efficient semi-definite programming (SDP) to solve the originally non-convex problem of antenna selection. This has been accomplished by imposing the(More)
The problem of joint zero-forcing (ZF) beamforming (BF) together with optimal power allocation (PA) and antenna selection (AS) for throughput maximization is considered in this paper for multi-user multiple input single output (MU-MISO) systems. We introduce a new formulation for the joint ZF and PA problem by adapting the algebraic subspace approach which(More)
Acknowledgement This master thesis is defined by ArrayComm company in U.S, California, San Jose. The project is a collaboration between the company and Chalmers. I would like to show my gratitude to certain people: Dr. Thomas Svantesson from ArrayComm-for giving me this opportunity and also your great guidance and help during the project. Professor Mats(More)
Neural networks are powerful computational tools, and have been applied in various applications. In this work, a neural network has been used to solve a pattern classification problem encountered in biochemistry. One of the major topics of research in molecular biology is the prediction of functional properties of biomacromolecules from their sequence data.(More)