Javier Perez-Ramirez

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Optimal placement of sensors or landmarks for the localization of an autonomous guided vehicle (AGV) based on range measurements is considered. The optimization relies on the Fisher information matrix (FIM). A closed-form expression of the FIM determinant is obtained for 2-D and 3-D spaces, considering heterogeneous sensors and distance-dependent ranging(More)
Turbo coded data transmission over a hybrid channel, consisting of parallel free space optical (FSO) and radio frequency (RF) links, is considered, and analytical bit error performance results are derived. The FSO link is modeled using the gamma-gamma distribution function, and both random and block fading channels are used. Random and specific codeword bit(More)
A single-input multiple-output optical communication system based on an LED transmitter and a receiving pixel grid of a camera is considered. The LED image received at a reference distance is modeled using a Gaussian mixture and the pixel values at any other desired distance are estimated using the reference image. Both optimal and suboptimal pixel(More)
A novel type-II hybrid automatic repeat request (HARQ) algorithm over hybrid channels, consisting of parallel free space optical (FSO) and radio frequency (RF) links, is presented. The algorithm uses different jointly optimized puncturing and RF bit selection patterns for different retransmissions. Analytical bit error rate and throughput performance(More)
In this work, a control structure to maintain the power flow transference in renewable energy systems based on wind turbines operating under unbalanced voltage conditions is presented. In the proposed scheme, the Back-to-Back (BTB) converter preserves the electrical cogeneration under the occurrence of voltage sags type B, C and D in three-phase systems.(More)
This paper presents a multiuser mobile optical wireless communication system that uses a single digital camera to receive signals transmitted by multiple users using light-emitting diode (LED) arrays. The key idea is to sample only the engaged camera pixels affected by the signals from the users. Toward this aim, image frames received during an acquisition(More)
Dual-role nodes that can work both as relays and also as anchors for joint communication and source localization are proposed. Selection and power allocation of a few dual-role nodes in the presence of many nodes in the network are considered. A novel approach is proposed that relies on maximizing the signal-to-noise ratio (SNR) at the destination node(More)
We investigate the behavior of spatially partially coherent beams (PCBs) in the presence of pointing errors in the space communication environment. Closed form expressions for the optimal coherence length for minimizing outage probability and maximizing average signal-to-noise ratio (SNR) are derived. In the case of outage probablity, we observe that the(More)
This work presents the extended capabilities of a single-phase Pulse Width Modulation (PWM) rectifier to achieve a unity power factor (PF) in the Point of Common Coupling (PCC). It can act as a dynamic var compensator, fixed var compensator and Active Power Filter (APF). To accomplish such tasks a control scheme based in two cascaded loops is used. The(More)
Estimation of the image location of a mobile LED array transmitter on the camera sensor plane of a digital camera is considered. A Bayesian framework is used to design an initial large measurement matrix over multiple image frames to exploit inter-frame temporal correlations. This large matrix is then factorized into two component matrices; one is used as(More)