Optimization of Radio and Computational Resources for Energy Efficiency in Latency-Constrained Application Offloading

Providing femto-access points (FAPs) with computational capabilities will allow (either total or partial) offloading of highly demanding applications from smart-phones to the so called femto-cloud. Such offloading promises to be beneficial in terms of battery saving at the mobile terminal (MT) and/or latency reduction in the execution of applications, whenever the energy and/or time required for the communication process are compensated by the energy and/or time savings that result from the remote computation at the FAPs. For this problem, we provide in this paper a framework for the joint optimization of the radio and computational resource usage exploiting the tradeoff between energy consumption and latency, and assuming that multiple antennas are available at the MT and the serving FAP. As a result of the optimization, the optimal communication strategy (e.g., transmission power, rate, precoder) is obtained, as well as the optimal distribution of the computational load between the handset and the serving FAP. The paper also establishes the conditions under which total or no offloading are optimal, determines which is the minimum affordable latency in the execution of the application, and analyzes as a particular case the minimization of the total consumed energy without latency constraints.Comment: Accepted to be published at IEEE Transactions on Vehicular Technology (acceptance: November 2014

The topic of death in the poetry of Walt Whitman, Emily Dickinson, Sylvia Plath and Anne Sexton

Treballs Finals del Grau d'Estudis Anglesos, Facultat de Filologia, Universitat de Barcelona, Curs: 2016-2017, Tutora: Clara Escoda Agustí[eng] This dissertation aims to analyse the poems of Walt Whitman, Emily Dickinson, Sylvia Plath and Anne Sexton which are related to death, with a view to linking the poet’s biography to their poems and comparing the male and female attitudes to death. First of all, this study will contextualise different approaches to death that have taken place throughout the history of the West. Then, each poet or poetess will be given the biographical context necessary to read the poems regarding death. The poems of Whitman and Dickinson will be analysed in order to see to what extent they reflect the presence of the dead amongst the living. In addition to this, Plath’s and Sexton’s poems will also be analysed from the same perspective and starting on the basis that they both committed suicide. At this point, the study will seek to demonstrate if there are any relevant differences considering the fact of dying between the feminine and the masculine perspectives. Previous studies have not taken the poet’s biography into consideration and have not focused on specific authors, which is what this study intends to do.[cat] L'objectiu d'aquest estudi és analitzar els poemes de Walt Whitman, Emily Dickinson, Sylvia Plath i Anne Sexton relacionats amb la mort, tractant de connectar els seus poemes amb la biografia dels poetes i comparar, també, la perspectiva masculina i femenina sobre la mort. En primer lloc, aquest estudi contextualitzarà les visions que s'han donat de la mort al llarg de la història d'occident. A continuació, s'oferirà el context biogràfic necessari de cada poeta o poetessa per tal d'entendre els poemes que tracten la mort. Els poemes de Whitman i Dickinson s'analitzaran per tal de veure fins a quin punt reflecteixen la presència dels morts entre els vius. A més, els poemes de Plath i de Sexton s'analitzaran de la mateixa manera i també partint de la base que ambdues van suïcidar-se. En aquest punt, l'estudi pretén mostrar si hi ha cap diferència rellevant considerant la mort entre la perspectiva masculina i la femenina. Altres estudis previs no varen tenir en compte la biografia de l'autor i tampoc van centrar-se en autors específics, que és el què aquest estudi pretén fer

Approximations of the aggregated interference statistics for outage analysis in massive MTC

This paper presents several analytic closed-form approximations of the aggregated interference statistics within the framework of uplink massive machine-type-communications (mMTC), taking into account the random activity of the sensors. Given its discrete nature and the large number of devices involved, a continuous approximation based on the Gram–Charlier series expansion of a truncated Gaussian kernel is proposed. We use this approximation to derive an analytic closed-form expression for the outage probability, corresponding to the event of the signal-to-interference-and-noise ratio being below a detection threshold. This metric is useful since it can be used for evaluating the performance of mMTC systems. We analyze, as an illustrative application of the previous approximation, a scenario with several multi-antenna collector nodes, each equipped with a set of predefined spatial beams. We consider two setups, namely single- and multiple-resource, in reference to the number of resources that are allocated to each beam. A graph-based approach that minimizes the average outage probability, and that is based on the statistics approximation, is used as allocation strategy. Finally, we describe an access protocol where the resource identifiers are broadcast (distributed) through the beams. Numerical simulations prove the accuracy of the approximations and the benefits of the allocation strategy.Peer ReviewedPostprint (published version

Full field model for interleave-chirped arrayed waveguide gratings

© 2013 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedIn this paper, a theoretical model for an Interleave-Chirped Arrayed Waveguide Grating (IC-AWG) is presented. The model describes the operation of the device by means of a field (amplitude and phase) transfer response. The validation of the model is accomplished by means of simulations, using parameters from previously fabricated devices. A novel design procedure is derived from the model, and it is later on employed to demonstrate the design of colorless universal IC-AWGs. The model can be readily applied to the analysis and design of future multi-wavelength optical coherent communications receivers and optical waveform analyzers.The authors acknowledge financial support by the Spanish MICINN Project TEC2010-21337, acronym ATOMIC; project FEDER UPVOV10-3E-492 and project FEDER UPVOV08-3E-008. B. Gargallo acknowledges financial support through FPI grant BES-2011-046100.Gargallo Jaquotot, BA.; Muñoz Muñoz, P. (2013). Full field model for interleave-chirped arrayed waveguide gratings. Optics Express. 21(6):6928-6942. https://doi.org/10.1364/OE.21.006928S69286942216Nagarajan, R., Kato, M., Lambert, D., Evans, P., Corzine, S., Lal, V., … Welch, D. (2012). Terabit/s class InP photonic integrated circuits. Semiconductor Science and Technology, 27(9), 094003. doi:10.1088/0268-1242/27/9/094003Soldano, L. B., & Pennings, E. C. M. (1995). Optical multi-mode interference devices based on self-imaging: principles and applications. Journal of Lightwave Technology, 13(4), 615-627. doi:10.1109/50.372474Bachmann, M., Besse, P. A., & Melchior, H. (1994). General self-imaging properties in N × N multimode interference couplers including phase relations. Applied Optics, 33(18), 3905. doi:10.1364/ao.33.003905Heaton, J. M., & Jenkins, R. M. (1999). General matrix theory of self-imaging in multimode interference (MMI) couplers. IEEE Photonics Technology Letters, 11(2), 212-214. doi:10.1109/68.740707Van Roey, J., van der Donk, J., & Lagasse, P. E. (1981). Beam-propagation method: analysis and assessment. Journal of the Optical Society of America, 71(7), 803. doi:10.1364/josa.71.000803Doerr, C. R., Zhang, L., & Winzer, P. J. (2011). Monolithic InP Multiwavelength Coherent Receiver Using a Chirped Arrayed Waveguide Grating. Journal of Lightwave Technology, 29(4), 536-541. doi:10.1109/jlt.2010.2097240Munoz, P., Pastor, D., & Capmany, J. (2002). Modeling and design of arrayed waveguide gratings. Journal of Lightwave Technology, 20(4), 661-674. doi:10.1109/50.996587Talahashi, H., Oda, K., Toba, H., & Inoue, Y. (1995). Transmission characteristics of arrayed waveguide N×N wavelength multiplexer. Journal of Lightwave Technology, 13(3), 447-455. doi:10.1109/50.372441Wan, Y., & Hui, R. (2007). Design of WDM Cross Connect Based on Interleaved AWG (IAWG) and a Phase Shifter Array. Journal of Lightwave Technology, 25(6), 1390-1400. doi:10.1109/jlt.2007.896808Spiekman, L. H., Amersfoort, M. R., De Vreede, A. H., van Ham, F. P. G. M., Kuntze, A., Pedersen, J. W., … Smit, M. K. (1996). Design and realization of polarization independent phased array wavelength demultiplexers using different array orders for TE and TM. Journal of Lightwave Technology, 14(6), 991-995. doi:10.1109/50.511599LOHMEYER, M. (1997). Optical and Quantum Electronics, 29(9), 907-922. doi:10.1023/a:1018581701193Smit, M. K., & Van Dam, C. (1996). PHASAR-based WDM-devices: Principles, design and applications. IEEE Journal of Selected Topics in Quantum Electronics, 2(2), 236-250. doi:10.1109/2944.577370Fontaine, N. K., Scott, R. P., Zhou, L., Soares, F. M., Heritage, J. P., & Yoo, S. J. B. (2010). Real-time full-field arbitrary optical waveform measurement. Nature Photonics, 4(4), 248-254. doi:10.1038/nphoton.2010.28Bernasconi, P., Doerr, C., Dragone, C., Cappuzzo, M., Laskowski, E., & Paunescu, A. (2000). Large N x N waveguide grating routers. Journal of Lightwave Technology, 18(7), 985-991. doi:10.1109/50.85074

Analysis of System Imperfections in a Photonics-Assisted Instantaneous Frequency Measurement Receiver Based on a Dual-Sideband Suppressed-Carrier Modulation

[EN] Instantaneous frequency measurement receivers are a well-established technology that is used for the ultrafast characterization of pulsed microwave signals over a broad bandwidth. Recently, numerous photonic approaches to instantaneous frequency measurement (IFM) have been proposed and experimentally demonstrated, with the ultimate aim of leveraging the benefits of optical technology to improve the performance of already existent electronic solutions. Despite the numerous results, not so much attention has been paid so far to understand the subtle implications that system imperfections can have on realistic photonics-based IFM receivers. Here, we focus our attention on one of the most promising among these IFM techniques, which is based on optical power monitoring of a dual-sideband suppressed-carrier modulation after a Mach Zehnder interferometer (MZI) filter. We develop a time-domain model for the rigorous analysis of all major optical and electrical effects, including amplitude imbalance and phase errors in the modulator and the MZI, as well as on-pulse RF phase/frequency modulation. Simulations are then used to illustrate the substantial effect that a nonperfectly suppressed optical carrier can have on system performance. More importantly, it is shown that in a nonideal situation, the system amplitude comparison function critically depends on input RF power, thus greatly limiting the dynamic range of the photonics-based receiver. Some approaches to solve these issues are also discussed.This work was supported by projects TEC2010-21337 (ATOMIC), FEDER UPVOV10-3E-492, FEDER UPVOV08-3E-008, TEC2013-42332-P (PIC4ESP), and PROMETEO 2013/012. The work of J. S. Fandino was supported by Grant FPU-2010 (ref: AP2010-1595).Sánchez Fandiño, JA.; Muñoz Muñoz, P. (2015). Analysis of System Imperfections in a Photonics-Assisted Instantaneous Frequency Measurement Receiver Based on a Dual-Sideband Suppressed-Carrier Modulation. Journal of Lightwave Technology. 33(2):293-303. https://doi.org/10.1109/JLT.2014.2378331S29330333

Photonics-based microwave frequency measurement using a double-sideband suppressed-carrier modulation and an InP integrated ring-assisted Mach Zehnder interferometer filter

© [2013 Optical Society of America.]. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited.[EN] A photonic system capable of estimating the unknown frequency of a CW microwave tone is presented. The core of the system is a complementary optical filter monolithically integrated in InP, consisting of a ring-assisted Mach-Zehnder interferometer with a second-order elliptic response. By simultaneously measuring the different optical powers produced by a double-sideband suppressed-carrier modulation at the outputs of the photonic integrated circuit, an amplitude comparison function that depends on the input tone frequency is obtained. Using this technique, a frequency measurement range of 10 GHz (5-15 GHz) with a root mean square value of frequency error lower than 200 MHz is experimentally demonstrated. Moreover, simulations showing the impact of a residual optical carrier on system performance are also provided. (C) 2013 Optical Society of AmericaThis work was supported by projects TEC2010-21337 (ATOMIC), FEDER UPVOV10-3E-492, and UPVOV08-3E-008. J. S. Fandino was supported by grant FPU-2010 (ref: AP2010-1595). The authors acknowledge the use of Phoenix Software tools for design of the InP PIC, which was manufactured within the EuroPIC FP7 project (ref: NMP 228839-2).Sánchez Fandiño, JA.; Muñoz Muñoz, P. (2013). Photonics-based microwave frequency measurement using a double-sideband suppressed-carrier modulation and an InP integrated ring-assisted Mach Zehnder interferometer filter. Optics Letters. 38(21):4316-4319. https://doi.org/10.1364/OL.38.004316S43164319382