Mehrzad Biguesh - Academia.edu (original) (raw)

Papers by Mehrzad Biguesh

IEEE Transactions on Audio, Speech, and Language Processing, 2012

Iet Communications, Jul 1, 2014

The authors consider a half-duplex asynchronous code division multiple access cooperative network... more The authors consider a half-duplex asynchronous code division multiple access cooperative network with N sourcedestination (SD) pairs and a number of relay nodes where the nodes of all pairs have to exchange data in two hops via assistance of one of the available relays. In this study, they minimise the total transmit power and derive the closed-form solution for choosing the best relay, the best relay gain and the transmit powers of all sources where some predefined signal-to-interference plus noiseratios (SINRs) are guaranteed. Interestingly, the feasibility condition of the problem depends only on the required SINRs, the number of SD pairs and the maximum cross-correlation of users' codes. They suggest two control procedures for admitting or dropping of users to the network to satisfy the feasibility condition. For a reciprocal environment, the best relay and its gain are proved to remain unchanged for reversing the communication directions. In addition, the authors' power control algorithm can be directly applied to the case of two-hop two-way relaying. Computer simulations are used to demonstrate the system performance.

The contribution of this paper is two-fold. First, we introduce a generalized principal component... more The contribution of this paper is two-fold. First, we introduce a generalized principal component (GPC) beamforming technique for reduced rank processing that allows a trade-off between interference and noise reduction via the introduction of a control parameter, : Three variants of the GPC beamformer corresponding to 1 (called T1 beamformer), 0:5 (called T2 beamformer) and 0 (called T3 beamformer), which maximize the signal-to-interference ratio, the signal-to-interference plus noise ratio, and the signal-to-noise ratio at the array output respectively, are considered in detail. The second contribution of this paper is to compare the robustness between the reduced rank and full rank beamformers. We use analytical studies and computer simulations to show that the T2 and T3 beamformers are robust against calibration and/or pointing errors.

Industrial Electronics and Engineering, 2014

Eurasip Journal on Wireless Communications and Networking, Dec 1, 2004

A serious shortcoming of current downlink power control methods is that their performance may be ... more A serious shortcoming of current downlink power control methods is that their performance may be severely degraded when the downlink channel information is known imprecisely at the transmitter. In this paper, a computationally and implementationally simple centralized downlink power control method is proposed for cellular wireless communication systems using code division multiple access (CDMA) or space division multiple access (SDMA). Our method provides a substantially improved robustness against imperfect knowledge of the wireless channel by means of maintaining the required quality of service for the worst-case channel uncertainty. In the SDMA case, the proposed technique can be straightforwardly combined with any of the existing transmit beamforming methods. Simulation results validate substantial robustness improvements achieved by our approach.

Energy, May 1, 2020

In this manuscript, a decentralized and heuristic energy consumption scheduling scheme is propose... more In this manuscript, a decentralized and heuristic energy consumption scheduling scheme is proposed for implementing the day-ahead price-based demand side management program in a power distribution network. A customer, who participates in the proposed scheme, profits by minimizing his consumption cost and taking into account his own financial benefits and operational needs. This is done for each customer without a need for iterative interaction and other customers' consumption information. Also, the supplier takes advantage of this scheme, by controlling the aggregate network consumption peak through solving a simplified optimization problem, which needs less information about customers' consumption. The customers' privacy is preserved in this scheme, because no individual behaviour, in the forthcoming scheduling time horizon, can be extracted from the data sent to the supplier. Besides, in one sense it is a fair solution because the less customer's consumption peak is, the more relative financial benefit he gets. In our simulated case study, the proposed scheme was compared to the most related scheme, where the Commonwealth Edison company day-ahead pricing data-set is employed. The results show that the aggregate network consumption peak of our scheme is controllable, even when the percentage of the participant customers increases.

Abstract The time varying channel between transmitter and receiver in wireless communications nec... more Abstract The time varying channel between transmitter and receiver in wireless communications necessitates the receiver to be informed about the channel between the transmitter and the receiver periodically in the detection procedure. This paper introduces a geometrical model for channel matrix in a multiple-input multiple-output (MIMO) communication system, where the channel is supposed to be fast fading. Then an auto regressive (AR) model is proposed for the channel matrix variations at each time instant, ...

Abstract Power control is one of the most efficient approaches to increase the capacity and quali... more Abstract Power control is one of the most efficient approaches to increase the capacity and quality of service (QoS) in cellular communication systems. Existing power control approaches are mostly suitable for environments with quasi-stationary channels, while in practice, the channel characteristics may vary very fast with time. Therefore these approaches do not accurately capture the the dynamics of a real channel. In this paper we propose a new method of power control in wireless networks with Rayleigh fading signals. ...

IEEE Signal Processing Letters, 2010

Abstract In this letter, we consider a power allocation problem for digital subscriber line (DSL)... more Abstract In this letter, we consider a power allocation problem for digital subscriber line (DSL) systems. The goal of this problem is to minimize the total transmit power under some constraints on minimum data-rate and maximum transmit power for each modem where we take into account various sources of interference. We convert our problem into an auxiliary geometric programming (GP) which gives the optimum solution for transmit powers in a neighborhood of a given feasible point. Then, we use an iterative scheme for obtaining the ...

Iet Communications, Oct 16, 2012

This paper investigates the fundamental capacity limits of opportunistic spectrum-sharing channel... more This paper investigates the fundamental capacity limits of opportunistic spectrum-sharing channels in fading environments. The concept of opportunistic spectrum access is motivated by the frontier technology of cognitive radio which offers a tremendous potential to improve the utilization of the radio spectrum by implementing efficient sharing of the licensed spectrum. In this spectrum-sharing technology, a secondary user may utilize the primary user's licensed band as long as its interference to the primary receiver remains below a tolerable level. Herein, we consider that the secondary user's transmission has to adhere to limitations on the ensuing received power at the primary's receiver, and investigate the capacity gains offered by this spectrum-sharing approach in a Rayleigh fading environment. Specifically, we derive the fading channel capacity of a secondary user subject to both average and peak received-power constraints at the primary's receiver. In particular, considering flat Rayleigh fading, we derive the capacity and optimum power allocation scheme for three different capacity notions, namely, ergodic, outage, and minimum-rate, and provide closed-form expressions for these capacity metrics. Numerical simulations are conducted to corroborate our theoretical results.

IEEE Transactions on Signal Processing, Mar 1, 2006

IEEE Signal Processing Letters, 2021

Joint power optimization of sources and relay in cooperative networks, while multiple source-dest... more Joint power optimization of sources and relay in cooperative networks, while multiple source-destination (SD) pairs are utilizing a relay and also have direct transmission links, is addressed in this letter. In the assumed network each SD pair requires a minimum quality of service (QoS) in terms of its received SINR. We have shown that the resulted power control equations are quadratic due to coexistence of direct and relay links. The feasibility analysis of the resulted non-convex optimization problems is complicated. The necessary condition for the optimization problem feasibility is studied and two upper bounds for the achievable SINR of the users are derived. Computer simulations are used to study the achievable SINRs and the results are compared with the obtained upper bounds.

Journal of Iranian Association of Electrical and Electronics Engineers, 2018

IEEE Transactions on Aerospace and Electronic Systems, 2019

Various methods have been proposed for passive localization by using a network of sensors measuri... more Various methods have been proposed for passive localization by using a network of sensors measuring different parameters such as AOA, TDOA, FDOA, differential received signal strength (DRSS), the gain ratio of arrival (GROA), or a combination of these pieces of information. In this paper, a method for target localization based on power of received signal in multiple stations has been proposed for two scenarios. In one scenario, the receiving antennas are omni-directional and in the other scenario they are directional. We have derived a closed-form solution for source localization in the first scenario and we have proposed two methods (i.e. random search and Taylor series) for estimating the target location in the second scenario. Using computer simulations, the performance of our methods was compared with the CRLB and it was shown that the proposed scheme outperforms conventional AOA-only measurement methods. Also, the effect of estimation error of parameter n (which is related to the signal propagation pathloss exponent in the environment) on the performance of the proposed method was analyzed and it was concluded that it has no significant influence on the performance of the proposed method. Finally, the performance of the proposed method has been evaluated using the real RSS data.

Proceedings of the Tenth IEEE Workshop on Statistical Signal and Array Processing (Cat. No.00TH8496)

A new beamforming algorithm, based on the eigendecomposion of the sample correlation matrix, has ... more A new beamforming algorithm, based on the eigendecomposion of the sample correlation matrix, has been introduced. The beamformer uses a weighted linear combination of the signal eigenvectors. Three versions of the beamformer have been proposed. It is shown that the proposed beamformer is a generalization of the delay-and-sum and the minimum variance beamformers. A linearly constrained minimum variance beamformer has also been derived. It is shown that the proposed approach induces robust beamformers.