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.
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. ...
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 ...
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.
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.
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. ...
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 ...
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.
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Papers by Mehrzad Biguesh