Access profile

Ideal applicants are holders of master’s degrees in Information and Communication Technologies, and preferably Telecommunications Engineering. However, the multidisciplinary nature of some of the Department’s research groups makes it desirable to consider admitting candidates with other degrees in the fields of physics, computing, biology and computational linguistics.

In addition to this academic profile, certain characteristics are considered important for applicants to have, including interest in the research projects being carried out in the Department, having critical and analytical abilities, having initiative, being consistent and persistent in their work and being able to work in a team.

Degree classifications:

• Direct admission: European Master of Science in Research on Information and Communication Technologies (MERIT) and Master of Science in Communication and Network Engineering (COMNET). This last programme has not been submitted for verification, but it is expected to be verified very soon.
• Preferential admission: other postgraduate programmes in the field of ICT engineering: telecommunications engineering, telematic engineering, computer sciences and photonic technologies.
• Others: depending upon the presence of other multidisciplinary research groups in the Department, applicants with degrees from other programmes that do not coincide with the aforementioned profiles will also be considered: informatics, physical sciences, chemistry, mathematics, biology and computational linguistics.

An appropriate level of English is required for this programme.

Output profile

Doctoral candidates who complete a doctoral degree will have acquired the following competencies, which are needed to carry out quality research (Royal Decree 99/2011, of 28 January, which regulates official doctoral studies):

a) A systematic understanding of the field of study and a mastery of the research skills and methods related to the field.
b) An ability to conceive, design or create, put into practice and adopt a substantial process of research or creation.
c) An ability to contribute to pushing back the frontiers of knowledge through original research.
d) A capacity for critical analysis and an ability to assess and summarise new and complex ideas.
e) An ability to communicate with the academic and scientific community and with society in general as regards their fields of knowledge in the manner and languages that are typical of the international scientific community to which they belong.
f) An ability to foster scientific, technological, social, artistic and cultural progress in academic and professional contexts within a knowledge-based society.

The award of a doctoral degree must equip the graduate for work in a variety of settings, especially those requiring creativity and innovation. Doctoral graduates must have at least acquired the personal skills needed to:

a) Develop in contexts in which there is little specific information.
b) Find the key questions that must be answered to solve a complex problem.
c) Design, create, develop and undertake original, innovative projects in their field.
d) Work as part of a team and independently in an international or multidisciplinary context.
e) Integrate knowledge, deal with complexity and make judgements with limited information.
f) Offer criticism on and intellectually defend solutions.

Finally, with respect to competencies, doctoral students must:
a) have acquired advanced knowledge at the frontier of their discipline and demonstrated, in the context of internationally recognised scientific research, a deep, detailed and well-grounded understanding of theoretical and practical issues and scientific methodology in one or more research fields;
b) have made an original and significant contribution to scientific research in their field of expertise that has been recognised as such by the international scientific community;
c) have demonstrated that they are capable of designing a research project that serves as a framework for carrying out a critical analysis and assessment of imprecise situations, in which they are able to apply their contributions, expertise and working method to synthesise new and complex ideas that yield a deeper knowledge of the research context in which they work;
d) have developed sufficient autonomy to set up, manage and lead innovative research teams and projects and scientific collaborations (both national and international) within their subject area, in multidisciplinary contexts and, where appropriate, with a substantial element of knowledge transfer;
e) have demonstrated that they are able to carry out their research activity in a socially responsible manner and with scientific integrity;
f) have demonstrated, within their specific scientific context, that they are able to make cultural, social or technological advances and promote innovation in all areas within a knowledge-based society;
g) have demonstrated that they are able to participate in scientific discussions at the international level in their field of expertise and disseminate the results of their research activity to audiences of all kinds.

Number of places

30

Duration of studies and dedication regime

Duration
The maximum period of study for full-time doctoral studies is three years, counted from the date of admission to the programme to the date of submission of the doctoral thesis. The academic committee of the doctoral programme may authorise a doctoral candidate to pursue doctoral studies on a part-time basis. In this case, the maximum period of study is five years, counting from the date of admission to the programme to the date of submission of the doctoral thesis. For calculating these periods, the date of admission is considered to be the date of the first enrolment for tutorials, and the date of submission the moment in which the Doctoral School officially deposits the doctoral thesis.

For full-time doctoral candidates, the minimum period of study is two years, counted from the date of an applicant's admission to the programme until the date on which the doctoral thesis is deposited; for part-time doctoral candidates it is four years. When there are justified grounds for doing so, and the thesis supervisor and academic tutor have given their authorisation, doctoral candidates may request that the academic committee of their doctoral programme exempt them from the minimum period of study requirement.

The calculation of periods of study will not include periods of absence due to illness, pregnancy or any other reason provided for in the regulations in force. Students who find themselves in any of these circumstances must notify the academic committee of the doctoral programme, which, where appropriate, must inform the Doctoral School. Doctoral candidates may also temporarily withdraw from the programme for up to one year, and this period may be extended for an additional year. Doctoral candidates who wish to interrupt their studies must submit a justified request to the academic committee of the doctoral programme, which will decide whether or not to approve the request. Each programme will establish conditions for readmission to doctoral studies.

Extension
If full-time doctoral candidates have not applied to deposit their thesis by the end of the three-year period of study, the academic committee of the programme may authorise an extension of up to one year. In exceptional circumstances, a further one-year extension may be granted, subject to the conditions established by the corresponding doctoral programme. In the case of part-time doctoral candidates, an extension of two years may be authorised. In both cases, in exceptional circumstances a further one-year extension may be granted by the Doctoral School's Standing Committee, upon the submission of a reasoned application by the academic committee of the doctoral programme.

Dismissal from the doctoral programme
A doctoral candidate may be dismissed from a doctoral programme for the following reasons:

• The doctoral candidate submitting a justified application to withdraw from the programme.
• The maximum period of study and of extensions thereof ending.
• The doctoral candidate not having enrolled every academic year (unless he or she has been authorised to temporarily withdraw).
• The doctoral candidate failing two consecutive assessments.
• The doctoral candidate having disciplinary proceedings filed against him or her that rule that he or she must be dismissed from the UPC.

Dismissal from the programme implies that doctoral candidates cannot continue studying at the UPC and the closing of their academic record. This notwithstanding, they may apply to the academic committee of the programme for readmission and the committee must reevaluate them in accordance with the criteria established in the regulations.

Organization

• Comellas Colome, Jaume

• Ferrus Ferre, Ramon
• Mateu Mateu, Jordi
• Vall-Llossera Ferran, Mercè
• Villares Piera, Nemesio Javier

• Department of Signal Theory and Communications (PROMOTORA)

Doctoral Unit - ICT North Campus Management and Support Unit (UTGCNTIC)

C. Jordi Girona, 1-3. Building B4-003 (North Campus)
Tel.: 934 017 233
E-mail: doctorat.tsc@upc.edu

Access profile

Ideal applicants are holders of master’s degrees in Information and Communication Technologies, and preferably Telecommunications Engineering. However, the multidisciplinary nature of some of the Department’s research groups makes it desirable to consider admitting candidates with other degrees in the fields of physics, computing, biology and computational linguistics.

In addition to this academic profile, certain characteristics are considered important for applicants to have, including interest in the research projects being carried out in the Department, having critical and analytical abilities, having initiative, being consistent and persistent in their work and being able to work in a team.

Degree classifications:

• Direct admission: European Master of Science in Research on Information and Communication Technologies (MERIT) and Master of Science in Communication and Network Engineering (COMNET). This last programme has not been submitted for verification, but it is expected to be verified very soon.
• Preferential admission: other postgraduate programmes in the field of ICT engineering: telecommunications engineering, telematic engineering, computer sciences and photonic technologies.
• Others: depending upon the presence of other multidisciplinary research groups in the Department, applicants with degrees from other programmes that do not coincide with the aforementioned profiles will also be considered: informatics, physical sciences, chemistry, mathematics, biology and computational linguistics.

An appropriate level of English is required for this programme.

Access requirements

Applicants must hold a Spanish bachelor’s degree or equivalent and a Spanish master’s degree or equivalent, provided they have completed a minimum of 300 ECTS credits on the two degrees (Royal Decree 43/2015, of 2 February)

In addition, the following may apply:

• Holders of an official degree awarded by a university in Spain or any other country in the European Higher Education Area, pursuant to the provisions of Article 16 of Royal Decree 1393/2007, of 29 October, which establishes official university course regulations, who have completed a minimum of 300 ECTS credits on official university degrees, of which at least 60 must be at the master's degree level.
• Holders of an official Spanish bachelor’s degree comprising at least 300 credits, as provided for by EU regulations. Holder of degrees of this kind must complete bridging courses unless the curriculum of the bachelor’s degree in question included research training credits equivalent in value to those which would be earned on a master's degree.
• Holders of an official university qualification who, having passed the entrance examination for specialised medical training, have completed at least two years of a training course leading to an official degree in a health-sciences specialisation.
• Holders of a degree issued under a foreign education system. In these cases, homologation is not required, but the UPC must verify that the degree certifies a level of training equivalent to an official Spanish master's degree and qualifies the holder for admission to doctoral studies in the country where it was issued. Admission on this basis does not imply homologation of the foreign degree or its recognition for any purpose other than admission to doctoral studies.
• Holders of a Spanish doctoral qualification issued under previous university regulations.

Note 1: Doctoral studies entrance regulations for holders of an undergraduate degree awarded before the introduction of the EHEA (CG 47/02 2014)

Note 2: Governing Council Decision 64/2014, which approves the procedure and criteria for assessing the fulfilment of academic admission requirements for doctoral studies by holders of non-homologated foreign degrees (CG 25/03 2014)

Admission criteria and merits assessment

• Appropriateness of academic background with the activities carried out in the proposed research group: 25%.
• Knowledge of the English language: 20%.
• Quality of university from which previous degree was awarded: 10%.
• Motivation letter/letters of recommendation: 10%.

An assessment will be considered positive is an applicant is given a score of 3 or more out of 5.

Based on the content of the motivation letter and the applicant’s preparedness, the Postgraduate Committee will assign a thesis supervisor.

If candidates do not have a degree in some kind of ICT engineering, they will have to take the bridging courses recommended by their supervisors and the programme, whether courses from the associated master’s programmes (MET, MATT) or other ones.

Training complements

The Postgraduate Committee of the Signal Theory and Communications Department may require candidates to complete specific bridging courses. In this case, the Committee will monitor the bridging courses and set up appropriate criteria to limit their length.

The courses shall involve training in research, but in no case will candidates be required to enrol in 60 or more ECTS credits (according to the academic regulations for doctoral studies, bridging courses could include transversal education, but there are plans to change to this so that these bridging courses exclusively provide research credits, especially in cases involving doctoral programmes with 300 ECTS credits).

Depending on the activities completed by the candidates, the Postgraduate Committee of the Signal Theory and Communications Department may propose measures, in addition to those established by current regulations, that would disassociate candidates who do not meet the established requisites.

The Postgraduate Committee may require candidates who are to be admitted to complete certain bridging courses in order to better adapt their profiles to the programme’s requirements regarding the knowledge necessary to properly complete the doctoral studies.

No bridging courses will be required for those who graduated from the MET, MASTEAM or MATT programmes, or any of the other previously mentioned ICT programmes.

For those who completed other programmes, the bridging coursework required will depend upon their backgrounds and the activities carried out by the research groups in which they will participate, and it could be up to 30 ECTS.

The courses to be taken are offered by the MET, MASTEAM or MATT programmes.

Also, depending on the characteristics of some of the Department’s research groups, courses from the following UPC programmes will also be considered:
• Master’s programme in Telecommunications Engineering
• Master’s programme in Electrical Engineering
• Master’s programme in Photonics
• Master’s programme in Innovation and Research in Informatics
• Master’s programme in Artificial Intelligence

After consulting with candidates’ supervisors, it will be the sole responsibility of the TSC Department’s Postgraduate Committee to determine which courses students will have to take to complete these bridging courses. In any case, the aim of the courses will always be to fill in the gaps that students are seen to have in their academic transcripts with regard to the activities carried out by the research group in which they will participate.

Enrolment period for new doctoral students

Students enrolling in the doctoral programme for the first time must do so by the deadline specified in the admission decision.
Unless otherwise expressly indicated, enrolments corresponding to admission decisions issued from the second half of April on must be completed within the ordinary enrolment period for the current academic year.

More information at the registration section for new doctoral students

Enrolment period

Ordinary period for second and successive enrolments: first half of October.

More information at the general registration section

Procedure for the preparation and defense of the research plan

Doctoral candidates must submit a research plan, which will be included in their doctoral student activity report, before the end of the first year. The plan may be improved over the course of the doctoral degree. It must be endorsed by the tutor and the supervisor, and it must include the method that is to be followed and the aims of the research.

At least one of these annual assessments will include a public presentation and defence of the research plan and work done before a committee composed of three doctoral degree holders, which will be conducted in the manner determined by each academic committee. The examination committee awards a Pass or Fail mark. A Pass mark is a prerequisite for continuing on the doctoral programme. Doctoral candidates awarded a Fail mark must submit a new research plan for assessment by the academic committee of the doctoral programme within six months.

The committee assesses the research plan every year, in addition to all of the other activities in the doctoral student activity report. Doctoral candidates who are awarded two consecutive Fail marks for the research plan will be obliged to definitely withdraw from the programme.

If they change the subject of their thesis, they must submit a new research plan.

Formation activities

Activity: Tutorial.
- Hours: 288.
- Type: compulsory.

Activity: Mobility.
- Hours: 480.
- Type: optional.

Activity: Assessment based on doctoral student activity report (DAD) and research plan.
- Hours: 4.
- Type: compulsory.

Activity: Training in information skills.
- Hours: 1,5.
- Type: compulsory.

Activity: Research methodology.
- Hours: 12.
- Type: compulsory.

Activity: Innovation and creativity.
- Hours: 8.
- Type: optional.

Activity: Language and communication skills.
- Hours: 18.
- Type: optional.

Activity: Courses and seminars.
- Hours: 50.
- Type: optional.

Activity: Workshops.
- Hours: 8.
- Type: optional.

Procedure for assignment of tutor and thesis director

The academic committee of the doctoral programme assigns a thesis supervisor to each doctoral candidate when they are admitted or enrol for the first time, taking account of the thesis supervision commitment referred to in the admission decision.

The thesis supervisor will ensure that training activities carried out by the doctoral candidate are coherent and suitable, and that the topic of the candidate’s doctoral thesis will have an impact and make a novel contribution to knowledge in the relevant field. The thesis supervisor will also guide the doctoral candidate in planning the thesis and, if necessary, tailoring it to any other projects or activities undertaken. The thesis supervisor will generally be a UPC professor or researcher who holds a doctoral degree and has documented research experience. This includes PhD-holding staff at associated schools (as determined by the Governing Council) and UPC-affiliated research institutes (in accordance with corresponding collaboration and affiliation agreements). When thesis supervisors are UPC staff members, they also act as the doctoral candidate’s tutor.

PhD holders who do not meet these criteria (as a result of their contractual relationship or the nature of the institution to which they are attached) must be approved by the UPC Doctoral School's Standing Committee in order to participate in a doctoral programme as researchers with documented research experience.

The academic committee of the doctoral programme may approve the appointment of a PhD-holding expert who is not a UPC staff member as a candidate’s thesis supervisor. In such cases, the prior authorisation of the UPC Doctoral School's Standing Committee is required. A UPC staff member who holds a doctoral degree and has documented research experience must also be proposed to act as a co-supervisor, or as the doctoral candidate’s tutor if one has not been assigned.

A thesis supervisor may step down from this role if there are justified reasons (recognised as valid by the committee) for doing so. If this occurs, the academic committee of the doctoral programme will assign the doctoral candidate a new thesis supervisor.

Provided there are justified reasons for doing so, and after hearing any relevant input from the doctoral candidate, the academic committee of the doctoral programme may assign a new thesis supervisor at any time during the period of doctoral study.

If there are academic reasons for doing so (an interdisciplinary topic, joint or international programmes, etc.) and the academic committee of the programme gives its approval, an additional thesis supervisor may be assigned. Supervisors and co-supervisors have the same responsibilities and academic recognition.

The maximum number of supervisors of a doctoral thesis is two: a supervisor and a co-supervisor.

For theses carried out under a cotutelle agreement or as part of an Industrial Doctorate, if necessary and if the agreement foresees it this maximum number of supervisors may not apply. This notwithstanding, the maximum number of supervisors belonging to the UPC is two.

More information at the PhD theses section

Permanence

The academic committee of the programme may authorise an extension of up to one year for full-time doctoral candidates who have not applied to deposit their thesis by the end of the three-year period of study, in the terms outlined in the Academic Regulations for Doctoral Studies of the Universitat Politècnica de Catalunya. In the case of part-time candidates, an extension of two years may be authorised. In both cases, in exceptional circumstances a further one-year extension may be granted by the Doctoral School's Standing Committee, upon the submission of a reasoned application by the academic committee of the doctoral programme.

A doctoral candidate may be dismissed from a doctoral programme for the following reasons:

• The doctoral candidate submitting a justified application to withdraw from the programme.
• The maximum period of study and of extensions thereof ending.
• The doctoral candidate not having enrolled every academic year (unless he or she has been authorised to temporarily withdraw).
• The doctoral candidate failing two consecutive assessments.
• The doctoral candidate having disciplinary proceedings filed against him or her that rule that he or she must be dismissed from the UPC.

Dismissal from the programme implies that doctoral candidates cannot continue studying at the UPC and the closing of their academic record. This notwithstanding, they may apply to the academic committee of the programme for readmission and the committee must reevaluate them in accordance with the criteria established in the regulations.

International Mention

The doctoral degree certificate may include International Doctorate mention. In this case, the doctoral candidate must meet the following requirements:

a) During the period of study leading to the award of the doctoral degree, the doctoral candidate must have spent at least three months at a respected higher education institution or research centre outside Spain to complete courses or do research work. The stays and activities carried out must be endorsed by the thesis supervisor and authorised by the academic committee of the programme. The candidate must provide a certifying document issued by the person responsible for the research group of the body or bodies where the stay or activity was completed. This information will be added to the doctoral student’s activity report.
b) Part of the thesis (at least the summary and conclusions) must be written and presented in one of the languages commonly used for science communication in the relevant field of knowledge, which must not be an official language of Spain. This rule does not apply to stays and reports in Spanish or to experts from Spanish-speaking countries.
c) At least two PhD-holding experts belonging to a higher education institution or research centre outside Spain must have issued officially certified reports on the thesis.
d) The thesis examination committee must have included at least one PhD-holding expert from a higher education or research institution outside Spain who was not responsible for the candidate’s stay abroad (point a) above).
e) The thesis defence must have taken place on UPC premises or, in the case of joint programmes, at the location specified in the collaboration agreement.

List of authorized thesis for defense

• LOCATELLI, FABIANO: Study and application of spectral monitoring techniques for optical network optimization
  
  Author: LOCATELLI, FABIANO
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Deposit date: 30/09/2021
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: SVALUTO MOREOLO, MICHELA | CHRISTODOULOPOULOS, KONSTANTINOS | FÀBREGA SÁNCHEZ, JOSEP MARIA
  Committee:
       CODIRECTOR: CHRISTODOULOPOULOS, KONSTANTINOS
       DIRECTOR: SVALUTO MOREOLO, MICHELA
       PRESIDENT: PAROLARI, PAOLA
       SECRETARI: GENE BERNAUS, JOAN MANUEL
       VOCAL NO PRESENCIAL: DELEZOIDE, CAMILLE
  Thesis abstract: One of the possible ways to address the constantly increasing amount of heterogeneous and variable internet traffic is the evolution of the current optical networks towards a more flexible, open, and disaggregated paradigm. In such scenarios, the role played by Optical Performance Monitoring (OPM) is fundamental. In fact, OPM allows to balance performance and specification mismatches resulting from the disaggregation adoption and provides the control plane with the necessary feedback to grant the optical networks an adequate automation level. Therefore, new flexible and cost-effective OPM solutions are needed, as well as novel techniques to extract the desired information from the monitored data and process and apply them.In this dissertation, we focus on three aspects related to OPM. We first study a monitoring data plane scheme to acquire the high resolution signal optical spectra in a nonintrusive way. In particular, we propose a coherent detection based Optical Spectrum Analyzer (OSA) enhanced with specific Digital Signal Processing (DSP) to detect spectral slices of the considered optical signals.Then, we identify two main placement strategies for such monitoring solutions, enhancing them using two spectral processing techniques to estimate signal- and optical filter-related parameters. Specifically, we propose a way to estimate the Amplified Spontaneous Emission (ASE) noise or its related Optical Signal-to-Noise (OSNR) using optical spectra acquired at the egress ports of the network nodes and the filter central frequency and 3/6 dB bandwidth, using spectra captured at the ingress ports of the network nodes. To do so, we leverage Machine Learning (ML) algorithms and the function fitting principle, according to the considered scenario. We validate both the monitoring strategies and their related processing techniques through simulations and experiments. The obtained results confirm the validity of the two proposed estimation approaches. In particular, we are able to estimate in-band the OSNR/ASE noise within an egress monitor placement scenario, with a Maximum Absolute Error (MAE) lower than 0.4 dB. Moreover, we are able to estimate the filter central frequency and 3/6 dB bandwidth, within an ingress optical monitor placement scenario, with a MAE lower than 0.5 GHz and 0.98 GHz, respectively. Based on such evaluations, we also compare the two placement scenarios and provide guidelines on their implementation. According to the analysis of specific figures of merit, such as the estimation of the Signal-to-Noise Ratio (SNR) penalty introduced by an optical filter, we identify the ingress monitoring strategy as the most promising. In fact, when compared to scenarios where no monitoring strategy is adopted, the ingress one reduced the SNR penalty estimation by 92%.Finally, we identify a potential application for the monitored information. Specifically, we propose a solution for the optimization of the subchannel spectral spacing in a superchannel. Leveraging convex optimization methods, we implement a closed control loop process for the dynamical reconfiguration of the subchannel central frequencies to optimize specific Quality of Transmission (QoT)-related metrics. Such a solution is based on the information monitored at the superchannel receiver side. In particular, to make all the subchannels feasible, we consider the maximization of the total superchannel capacity and the maximization of the minimum superchannel subchannel SNR value. We validate the proposed approach using simulations, assuming scenarios with different subchannel numbers, signal characteristics, and starting frequency values. The obtained results confirm the effectiveness of our solution. Specifically, compared with the equally spaced subchannel scenario, we are able to improve the total and the minimum subchannel SNR values of a four subchannel superchannel, of 1.45 dB and 1.19 dB, respectively.
  

Last update: 16/10/2021 04:47:07.

List of lodged theses

Last update: 16/10/2021 04:30:36.

List of defended theses by year

• GARCÍA PASTOR, DAVID: Nonlinear analysis of electro-acoustic frequency-selective devices for communications
  
  Author: GARCÍA PASTOR, DAVID
  Thesis link: http://hdl.handle.net/10803/671927
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Confidentiality
  Reading date: 09/03/2021
  Thesis director: MATEU MATEU, JORDI | COLLADO GOMEZ, JUAN CARLOS
  

  Committee:
       PRESIDENT: AIGNER, ROBERT
       SECRETARI: UBEDA FARRE, EDUARDO
       VOCAL NO PRESENCIAL: MIREA, TEONA
  Thesis abstract: Nowadays, mobile devices have become a key technology in our lives, making us become part of a connected world, in which millions of mobile handsets are sold every year. In order to satisfy the user demands, many mobile communication standards are working together in the same device (LTE-A, 5G-NR, IEEE Wireless LAN Standards, etc.). High data rates are demanded for different wireless services working on a very crowded frequency spectrum, where all the devices and systems need to operate at the same time without detrimental of mutual interference. Although this major objective has to be faced from different perspectives, such as new modulations and new networking protocols, the radio frequency (RF) and microwave components, forming the communication chain in a transceiver, play a significant role on the whole system performance. Passive devices, like filters, contribute to the signal degradation due to passive intermodulation (PIM). PIM can be generated by the lack of mismatch between metallic contacts, oxidation, or basically, by the inherent nonlinear material properties used on the fabrication of the devices. Although the impact of PIM is lower than the distortion introduced by active devices, for current wireless services and their demanding requirements, any type of nonlinear generation is certainly an issue.Acoustic wave (AW) devices have become a fundamental technology for portable handsets supporting current wireless communication networks. Bulk Acoustic Wave (BAW) has become the main technology nowadays for high frequency filters. This technology allows a high degree of miniaturization, easily making more than 40 filters per device, and also gives other advantages as low insertion losses and multiple frequency operation. Despite these major advantages, BAW resonators exhibit a nonlinear behavior, i.e., they may suffer of intermodulation and harmonic distortion, which might become a real bottle neck for the full expansion of the technology in the ever increasing stringent requirements.The aim of this thesis is focused on characterizing this nonlinear limitation, quite present in acoustic resonators, by defining the origin of different nonlinear manifestations in BAW resonators, and providing new nonlinear models to reduce the computational time required to simulate those undesired effects.The first part of this work explains the basic knowledge about acoustic propagation and piezoelectricity, presenting the linear and nonlinear constitutive equations, including the typical nonlinear manifestations appearing in those devices. Then, the typical circuit models for AW devices and, more specifically its applicability to BAW devices, is presented.The second part of this work is focused on the nonlinear analysis of BAW resonators, by measuring different nonlinear manifestation of 8 different BAW devices, identifying the origin of the nonlinear effects and demonstrating that this unique hypothesis is consistent with those manifestations for all the measured resonators.
  

• GIMÉNEZ FEBRER, PEDRO JUAN: Matrix completion with prior information in reproducing kernel Hilbert spaces
  
  Author: GIMÉNEZ FEBRER, PEDRO JUAN
  Thesis link: http://hdl.handle.net/10803/671718
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 11/02/2021
  Thesis director: PAGES ZAMORA, ALBA MARIA
  

  Committee:
       PRESIDENT: GARCÍA MARQUÉS, ANTONIO
       SECRETARI: RODRIGUEZ FONOLLOSA, JAVIER
       VOCAL NO PRESENCIAL: ROMERO GONZÁLEZ, DANIEL
  Thesis abstract: In matrix completion, the objective is to recover an unknown matrix from a small subset of observed entries. Most successful methods for recovering the unknown entries are based on the assumption that the unknown full matrix has low rank. By having low rank, each of its entries are obtained as a function of a small number of coefficients which can be accurately estimated provided that there are enough available observations. Hence, in low-rank matrix completion the estimate is given by the matrix of minimum rank that fits the observed entries.Besides low rankness, the unknown matrix might exhibit other structural properties which can be leveraged in the recovery process. In a smooth matrix, it can be expected that entries that are close in index distance will have similar values. Similarly, groups of rows or columns can be known to contain similarly valued entries according to certain relational structures. This relational information is conveyed through different means such as covariance matrices or graphs, with the inconvenient that these cannot be derived from the data matrix itself since it is incomplete. Hence, any knowledge on how the matrix entries are related among them must be derived from prior information. This thesis deals with matrix completion with prior information, and presents an outlook that generalizes to many situations. In the first part, the columns of the unknown matrix are cast as graph signals with a graph known beforehand. In this, the adjacency matrix of the graph is used to calculate an initial point for a proximal gradient algorithm in order to reduce the iterations needed to converge to a solution. Then, under the assumption that the graph signals are smooth, the graph Laplacian is incorporated into the problem formulation with the aim to enforce smoothness on the solution. This results in an effective denoising of the observed matrix and reduced error, which is shown through theoretical analysis of the proximal gradient coupled with Laplacian regularization, and numerical tests. The second part of the thesis introduces a framework to exploit prior information through reproducing kernel Hilbert spaces. Since a kernel measures similarity between two points in an input set, it enables the encoding of any prior information such as feature vectors, dictionaries or connectivity on a graph. By associating each column and row of the unknown matrix with an item in a set, and defining a pair of kernels measuring similarity between columns or rows, the missing entries can be extrapolated by means of the kernel functions. A method based on kernel regression is presented, with two additional variants aimed at reducing computational cost, and online implementation. These methods prove to be competitive with existing techniques, especially when the number of observations is very small. Furthermore, mean-square error and generalization error analyses are carried out, shedding light on the factors impacting algorithm performance. For the generalization error analysis, the focus is on the transductive case, which measures the ability of an algorithm to transfer knowledge from a set of labelled inputs to an unlabelled set. Here, bounds are derived for the proposed and existing algorithms by means of the transductive Rademacher complexity, and numerical tests confirming the theoretical findings are presented. Finally, the thesis explores the question of how to choose the observed entries of a matrix in order to minimize the recovery error of the full matrix. A passive sampling approach is presented, which entails that no labelled inputs are needed to design the sampling distribution; only the input set and kernel functions are required. The approach is based on building the best Nyström approximation to the kernel matrix by sampling the columns according to their leverage scores, a metric that arises naturally in the theoretical analysis to find an optimal sampling distribution.
  

• GIRBAU XALABARDER, ANDREU: Sports broadcasting and multiple object tracking with deep learning methods
  
  Author: GIRBAU XALABARDER, ANDREU
  Thesis link: http://hdl.handle.net/10803/671938
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Confidentiality
  Reading date: 17/03/2021
  Thesis director: MARQUES ACOSTA, FERNANDO | GIRÓ NIETO, XAVIER | RIUS FERRER, IGNASI
  

  Committee:
       PRESIDENT: SALGADO ALVAREZ DE SOTOMAYOR, LUIS
       SECRETARI: SALEMBIER CLAIRON, PHILIPPE
       VOCAL: CALDERERO PATINO, FELIPE
  Thesis abstract: Since less than a decade ago, deep learning techniques started to dominate many different fields, revolutionizing the possibilities of artificial intelligence. Seeing their potential, industrial sectors started to invest in applying such technologies as key components of the company strategy. This thesis has been developed in an industrial context, in AutomaticTV. The main focus along this period has been the transfer of knowledge and know-how between academia and industry, development of tools to exploit this knowledge, the exploration of new techniques for future challenges, and, from an academic research perspective, contributions to the multiple object tracking problem.The first part of the thesis is devoted to the introduction of deep learning technologies to AutomaticTV, a company dedicated to automatic sports analysis and broadcasting, and the development of tools and tasks that surround the application.The second part of this thesis introduces the contributions to the multiple object tracking challenge. We present TrajE, a trajectory estimator based on mixture density networks and beam search, used to boost the performance of existing multiple object trackers, and introduce an occlusion reconstruction step using the estimated trajectory information. By adding TrajE to an existing multiple object tracker, we boost its performance by 6.3, 1.8 points in MOTA and IDF1 scores respectively, becoming the new state of the art in the MOTChallenge dataset.
  

• GONZÁLEZ LÓPEZ, GISELLE: Wireless sensors embedded in high permittivity lossy media
  
  Author: GONZÁLEZ LÓPEZ, GISELLE
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Article-based thesis
  Reading date: 29/06/2021
  Thesis director: JOFRE ROCA, LUIS
  

  Committee:
       PRESIDENT: ANTONINO DAVIU, EVA
       SECRETARI: BROQUETAS IBARS, ANTONI
       VOCAL: LUXEY, CYRIL
  Thesis abstract: The design of wireless sensors for operation embedded in a medium with high losses creates a series of additional constraints that should be taken into consideration at design stage to enhance sensor performance. In such a medium, both the real and the imaginary part of the relative permittivity will have a high value. In this thesis, the effect of the imaginary part (which basically accounts for medium losses) on sensor performance and signal propagation will be analysed in detail.Although the attenuating effect the losses of this surrounding medium will have on a propagating microwave signal can be foreseen, there is still much to be learned with respect to how these dielectric properties impact the actual performance of the sensor, and how this effect may be prevented or mitigated at design stage. Furthermore, currently available set-ups to measure the performance of radiating devices have not been conceived to measure devices that do not operate in air.Bearing this in mind, this thesis intends to shed some light on the specific challenges encountered when designing devices for embedded operation in high permittivity lossy materials. This is done by means of two specific embedded application scenarios. In the first one a wireless RFID temperature sensor is placed inside a concrete structure to monitor the evolution of the setting process of concrete. Whereas in the second scenario a microwave bodyscope is used to monitor metallic implants inside the human body. Finally, in-field results are presented for both scenarios.High accuracy measurements of the evolution of concrete's relative permittivity over time and frequency are presented, which are then used as reference at sensor design stage. A specific analysis of the correlation between antenna performance and surrounding medium's dielectric properties is conducted and some preliminary design guidelines are provided. Furthermore, a novel miniaturized anechoic chamber for X-wave and embedded measurement is presented.
  

• HUELTES ESCOBAR, ALBERTO: Synthesis of acoustic wave filters. Ladder and transversal topologies. Towards a practical implementation
  
  Author: HUELTES ESCOBAR, ALBERTO
  Thesis link: http://hdl.handle.net/10803/671719
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Confidentiality
  Reading date: 05/02/2021
  Thesis director: COLLADO GOMEZ, JUAN CARLOS | MATEU MATEU, JORDI
  

  Committee:
       PRESIDENT: AIGNER, ROBERT
       SECRETARI: GILABERT PINAL, PERE LLUIS
       VOCAL NO PRESENCIAL: VILLANUEVA TORRIJO, LUIS GUILLERMO
  Thesis abstract: The meteoric growth of the mobile communication market for the last three decades has been strongly related with the evolution of the electroacoustic (EA) filter technology. With way over 5 billion cell phone users worldwide in 2017 and 5G standard in the horizon, the radiofrequency spectrum is becoming increasingly crowded whereas demand for mobile data has no expected limits in the short to medium term.In this scenario, where a unique filter needs to be designed for each band of operation, requirements for advanced filtering solutions continue to grow as well as the average value of the RF solutions and the RF content per mobile device.RF and microwave devices based on EA resonators such as Bulk Acoustic Wave (BAW) and Surface Acoustic Wave (SAW) filters overcame the limitations of the existent technologies back in the 1980¿s thanks to its compatibility with the manufacturing process of standard Silicon Integrated Circuits (Si-IC).Nowadays sophisticated RF Front-End (RFFE) Modules based on System-in-Package (SiP) are the key solution to integrate the increasing number of electronic parts - Power Amplifiers (PAs), Low Noise Amplifiers (LNAs) and switches - that accompanies acoustic filtering devices like filters, duplexers and multiplexers.Even though the level of complexity and accuracy present on the current EA devices is extraordinary, the design procedures for acoustic filters are still based on the optimization of built-in performance parameters from behavior-based compact models of resonators and the success on this duty relies mostly on the expertise of the designers. However due to the stringent technological constrains and the increasing complexity of the RFFE module architectures devoted to satisfy demanding specifications of the current and forthcoming communications standards, the challenging work of the designers is never getting easier. The aim of this work is focused on providing valuable insights that might help to overcome some of the existent limitations in the design of EA filters. Wider bandwidths, prescribed inclusion of external elements or multiplexing features are taken into consideration. On one hand we show a synthesis formulation and an automated procedure to carry out the synthesis for current well-known topologies, i.e. ladder, taking into consideration realistic values and specifications. On the other hand, a synthesis formulation for novel topologies, named here transversal, is provided. Success of this novel topology will certainly help to guarantee the prevalence of EA filters in the future communication standards, along with the extension to other applications with more stringent requirements and different operating frequencies. The first part of the work is devoted to explain the basic theory related to filter synthesis and its applicability to filters based on EA resonators. Subsequent chapters elaborate the theory to explain the procedures followed to obtain both synthesis and their limitations. Finally, a Chapter devoted to study cases shows the results of applying the filter synthesis to real case scenarios.
  

• KHAN, UMAIR: Self-supervised Deep Learning Approaches To Speaker Recognition
  
  Author: KHAN, UMAIR
  Thesis link: http://hdl.handle.net/10803/671496
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 11/01/2021
  Thesis director: HERNANDO PERICAS, FRANCISCO JAVIER
  

  Committee:
       PRESIDENT: GONZÁLEZ RODRÍGUEZ, JOAQUÍN
       SECRETARI: LUQUE SERRANO, JORGE
       VOCAL NO PRESENCIAL: GHAHABI ESFAHANI, OMID
  Thesis abstract: In speaker recognition, i-vectors have been the state-of-the-art unsupervised technique over the last few years, whereas x-vectors is becoming the state-of-the-art supervised technique, these days. Recent advances in Deep Learning (DL) approaches to speaker recognition have improved the performance but are constrained to the need of labels for the background data. In practice, labeled background data is not easily accessible, especially when large training data is required. In i-vector based speaker recognition, cosine and Probabilistic Linear Discriminant Analysis (PLDA) are the two basic scoring techniques. Cosine scoring is unsupervised whereas PLDA parameters are typically trained using speaker-labeled background data. This makes a big performance gap between these two scoring techniques. The question is: how to fill this performance gap without using speaker labels for the background data? In this thesis, the above mentioned problem has been addressed using DL approaches without using and/or limiting the use of labeled background data. Three DL based proposals have been made.In the first proposal, a Restricted Boltzmann Machine (RBM) vector representation of speech is proposed for the tasks of speaker clustering and tracking in TV broadcast shows. This representation is referred to as RBM vector. The experiments on AGORA database show that in speaker clustering the RBM vectors gain a relative improvement of 12% in terms of Equal Impurity (EI). For speaker tracking task RBM vectors are used only in the speaker identification part, where the relative improvement in terms of Equal Error Rate (EER) is 11% and 7% using cosine and PLDA scoring, respectively.In the second proposal, DL approaches are proposed in order to increase the discriminative power of i-vectors in speaker verification. We have proposed the use of autoencoder in several ways. Firstly, an autoencoder will be used as a pre-training for a Deep Neural Network (DNN) using a large amount of unlabeled background data. Then, a DNN classifier will be trained using relatively small labeled data. Secondly, an autoencoder will be trained to transform i-vectors into a new representation to increase their discriminative power. The training will be carried out based on the nearest neighbor i-vectors which will be chosen in an unsupervised manner. The evaluation was performed on VoxCeleb-1 database. The results show that using the first system, we gain a relative improvement of 21% in terms of EER, over i-vector/PLDA. Whereas, using the second system, a relative improvement of 42% is gained. If we use the background data in the testing part, a relative improvement of 53% is gained.In the third proposal, we will train a self-supervised end-to-end speaker verification system. The idea is to utilize impostor samples along with the nearest neighbor samples to make client/impostor pairs in an unsupervised manner. The architecture will be based on a Convolutional Neural Network (CNN) encoder, trained as a siamese network with two branch networks. Another network with three branches will also be trained using triplet loss, in order to extract unsupervised speaker embeddings. The experimental results show that both the end-to-end system and the speaker embeddings, despite being unsupervised, show a comparable performance to the supervised baseline. Moreover, their score combination can further improve the performance.The proposed approaches for speaker verification have respective pros and cons. The best result was obtained using the nearest neighbor autoencoder with a disadvantage of relying on background i-vectors in the testing. On the contrary, the autoencoder pre-training for DNN is not bound by this factor but is a semi-supervised approach. The third proposal is free from both these constraints and performs pretty reasonably. It is a self-supervised approach and it does not require the background i-vectors in the testing phase.
  

• MAHAJAN, ANKUSH: Machine learning assisted QoT estimation for optical networks optimization
  
  Author: MAHAJAN, ANKUSH
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 28/09/2021
  Thesis director: MARTINEZ RIVERA, RICARDO VICTOR | CHRISTODOULOPOULOS, KONSTANTINOS | MUÑOZ GONZALEZ, RAUL
  

  Committee:
       PRESIDENT: KIRSTADTER, ANDREAS
       SECRETARI: COMELLAS COLOME, JAUME
       VOCAL NO PRESENCIAL: TORNATORE, MASSIMO
  Thesis abstract: The tremendous increase in data traffic has spurred a rapid evolution of the optical networks for a reliable, affordable, cost effective and scalable network infrastructure. To meet some of these requirements, network operators are pushing toward disaggregation. Network disaggregation focuses on decoupling the traditional monolithic optical transport hardware into independent functional blocks that interoperate. This enables a relatively free market where the network operators/owners could choose the best-in-class equipment from different vendors overcoming the vendor lock-in, at better prices. In this multi-vendor disaggregation context, the used equipment would impact the physical layer and the overall network behavior. This results in increasing the uncertainty on the performance when compared to a traditional single vendor aggregated approach.For effective optical network planning, operation and optimization, it is necessary to estimate the Quality of Transmission (QoT) of the connections. Network designers are interested in accurate and fast QoT estimation for services to be established in a future or existing network. Typically, QoT estimation is performed using a Physical Layer Model (PLM) which is included in the QoT estimation tool or Qtool. A design margin is generally included in a Qtool to account for the modeling and parameter inaccuracies, to re-assure an acceptable performance. PLM accuracy is highly important as modeling errors translate into a higher design margin which in turn translate into wasted capacity or unwanted regeneration. Recently monitoring and machine learning (ML) techniques have been proposed to account for the actual network conditions and improving the accuracy of the PLM in single vendor networks. This in turn results in more accurate QoT estimation. The first part of the thesis focuses on the ML assisted accurate QoT estimation techniques. In this regard, we developed a model that uses monitoring information from an operating network combined with supervised ML regression techniques to understand the network conditions. In particular, we model the generated penalties due to i). EDFA gain ripple effect, and ii). filter spectral shape uncertainties at ROADM nodes. Furthermore, with the aim of improving the Qtool estimation accuracy in multi-vendor networks, we propose PLM extensions. In particular, we introduce four TP vendor dependent performance factors that capture the performance variations of multi-vendor TPs. To verify the potential improvement, we studied the following two use cases with the proposed PLM, to: i) optimize the transponders (TPs) launch power; and ii) reduce design margin in incremental planning. In consequence, the last part of this thesis aims at investigating and solving the issue of accuracy limitation of Qtool in dynamic optimization tasks. To keep the models aligned to the real conditions, the digital twin (DT) concept is gaining significant attention in the research community. The DT is more than a model of the system; it includes an evolving set of data, and a means to dynamically adjust the model. Based on the DT fundamentals, we devised and implemented an iterative closed control loop process that, after several intermediate iterations of the optimization algorithm, configures the network, monitors, and retrains the Qtool. For the Qtool retraining, we adopt a ML-based nonlinear regression fitting technique. The key advantage of this novel scheme is that whilst the network operates, the Qtool parameters are retrained according to the monitored information with the adopted ML model. Hence, the Qtool tracks the projected states intermediately calculated by the algorithm. This reduces the optimization time as opposed to directly probing and monitoring the network.
  

• MOLINA OLIVERAS, FRANCESC: Allocation designs for massive multiple access with interference cancellation
  
  Author: MOLINA OLIVERAS, FRANCESC
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 06/10/2021
  Thesis director: SALA ALVAREZ, JOSE
  

  Committee:
       PRESIDENT: LÓPEZ VALCARCE, ROBERTO
       SECRETARI: LAMARCA OROZCO, M. MERITXELL
       VOCAL NO PRESENCIAL: GAUDENZI, RICCARDO DE
  Thesis abstract: OliverasIn the transition towards the next generation of wireless technology systems, the increasing number of devices curbs the potential of current wireless networks to cope with such increases in network density. Wireless communications via satellite constitute a cost effective option to achieve high transmission reliability in remote areas or to create resilient networks to be used in emergency situations. To counterbalance the growing network density, one of the main goals in the uplink is to increase the spectral efficiency of the network. By working on the application of non-orthogonal multiple access and the exploitation of the collision domain through interference cancellation, this dissertation tackles the problem of massive multiple access. A consensual scheme that meets the main goal and the aim of reducing the interaction between devices and the satellite in the control plane is Enhanced Spread Spectrum ALOHA, which combines spreading-based short-packet transmissions with successive interference cancellation (SIC) on the receiver's side. This combination opens up several design avenues in terms of energy and code allocation to users when a certain amount of channel state information is available to them. Motivated by this scheme, this thesis studies the best allocation strategies when the SIC receiver operates nonideally: firstly, it investigates a system model for a receiver that, inspired by the demodulator adopted in the Enhanced Spread Spectrum ALOHA system, deals with the problems of user ordering and iterative decoding with short packets; and secondly, it delves into the user-asymptotic regime and the application of the calculus of variations to derive the stationary point equations corresponding to the optimal allocation rules.The first part of this thesis investigates the impact of nonideal decoding and imperfect cancellation on the first iteration of a SIC receiver aided by redundancy-check error control. The system model characterises both non-idealities using known functions of the signal-to-interference-plus-noise ratio. The propagation of packet decoding success/failure events throughout the stages of the receiver is circumvented in the user-asymptotic regime, since the model takes a deterministic form. The asymptotically optimal energy and rate allocation is studied for a wide variety of cases. The second part of this thesis investigates an iterative SIC receiver and extends the allocation designs derived previously to iterations beyond the first. The derivation of a system model is challenging, since each iteration of the receiver operates with memory with respect to the previous ones, and due to the fact that the decoding operations for the same user in different iterations are statistically dependent. This thesis motivates and states a system model that solves said difficulties by adding minimal complexity to the one adopted previously. The user-asymptotic regime is investigated to reveal mathematical forms to the above model that allow for a thorough understanding of the adopted receiver. Finally, the chapter exploits the user-asymptotic model and conducts research to designing smooth allocation functions. The third part of this thesis studies the user-ordering problem for a SIC receiver to which the strengths received from all users are unknown. The thesis derives an accurate system model for a large-user SIC receiver, which proceeds to order users after estimating their symbol energies at the initial stage through preamble cross-correlations. Analytical findings are determined in the user-asymptotic regime. The asymptotically optimal energy allocation is shown to obey, in contrast to the practically exponential user-energy distributions obtained before, a piecewise constant function; fact that entails great computational advantages of its application.
  

• MUÑOZ MARTIN, JOAN FRANCESC: Development of novel instruments and techniques for passive microwave remote sensing
  
  Author: MUÑOZ MARTIN, JOAN FRANCESC
  Thesis link: http://hdl.handle.net/10803/672272
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 17/06/2021
  Thesis director: CAMPS CARMONA, ADRIANO JOSE
  

  Committee:
       PRESIDENT: WICKERT, JENS
       SECRETARI: LOPEZ MARTINEZ, CARLOS
       VOCAL NO PRESENCIAL: RODRÍGUEZ ÁLVAREZ, NEREIDA
  Thesis abstract: Earth Observation using satellites has helped to better model our planet. The goal of such systems is to provide large data sets to help to understand the effects of our actions on the climate, to predict storms in near real-time, to prevent forest fires, or to prevent desertification, among others. In the last years, thanks to the miniaturization of electronics a new type of satellite have become popular, the CubeSat, a small spacecraft weighing from 1 to 10 kg, which can carry different types of instruments. Thanks to the cost reduction of these new platforms, new techniques can be easily evaluated, and the concept of a mesh of sensors surrounding the Earth is becoming a reality. Besides, the suitability of new techniques is being proven for such small spacecraft, such as GNSS reflectometry (GNSS-R). GNSS-R instruments are typically cheaper, more efficient (in terms of power consumption), and smaller than their traditional equivalent ones. This Ph.D. thesis is devoted to the development of passive microwave remote sensing instruments for CubeSats. However, before entering into the instrument design, several field experiments were proposed to model and validate the use of GNSS-R under different conditions. This Ph.D. thesis is divided into three main parts. The first part is devoted to assessing the capabilities of GNSS-R to retrieve different geophysical parameters through a different set of field experiments. First, the achievable spatial resolution of L1 and L5 GNSS-R signals is analyzed under different conditions. Second, taking into account the incoherent integration limits previously analyzed, the coherency of GNSS-R signals is analyzed at L1 and L5 bands. Third, thanks to the use of short integration times, multiple reflections received in the GPS L5 reflected signal could be identified as multiple peaks, thanks to the narrower auto-correlation function of such signals. Over the ocean, these multiple peaks are analyzed and linked to the sea state. Over the Australian rainforest, these multiple peaks at L5 are linked to multiple reflections on top of the vegetation canopy and in the bare soil. Fourth, a methodology to estimate soil moisture content over land using GNSS-R signals is proposed. Finally, the use of GNSS-R signals to estimate sea-ice thickness and snow content over the sea-ice is examined thanks to the data collected by a circular polarization GNSS-R instrument part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The second part of this dissertation is devoted to the design, implementation, and test of three passive microwave instruments for CubeSats. First, the Flexible Microwave Payload -1 (FMPL-1) is proposed as part of the 3Cat-4 mission. The instrument includes three experiments in a single platform: a total power L-band radiometer with frequent internal calibration, an L1/L2 GNSS reflectometer, and an AIS receiver. Second, the FMPL-2 instrument is proposed as the main payload of the 3Cat-5/A, one of the two instruments composing the ESA FSSCat mission, the first third-party mission contributing to the Copernicus system based on CubeSats. This second instrument is the evolved version of FMPL-1 and can provide synchronous GNSS-R and L-band radiometry data. Finally, a third instrument, the FMPL-3, is proposed for the GNSSaS mission of the NSSTC from the UAE. This third instrument includes the first-ever GNSS-R receiver at L5 and aims to prove the capabilities of such signals from space. Finally, in the third part, the first results of FMPL-2 are presented and analyzed. The instrument was successfully launched into a Low Earth Orbit during the Vega VV16 flight. First, the results of FMPL-2 during the first two weeks of in-orbit validation are presented. Data-driven algorithms to estimate sea-ice concentration, thickness, and soil moisture content over land are implemented using L-band microwave radiometry data and GNSS-R data retrieved by FMPL-2.
  

• TABARES GIRALDO, YEISON ALEJANDRO: Transmission impairments mitigation in next generation coherent optical access networks
  
  Author: TABARES GIRALDO, YEISON ALEJANDRO
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Reading date: 08/09/2021
  Thesis director: PRAT GOMA, JOSEP JOAN
  

  Committee:
       PRESIDENT: KILLEY, ROBERT
       SECRETARI: GENE BERNAUS, JOAN MANUEL
       VOCAL NO PRESENCIAL: FREUND, RONALD
  Thesis abstract: Worldwide, the coherent technologies have revolutionized the optical communication systems, significantly increasing the capacity of the fiber channel owing to transmission of advanced modulation formats and effective mitigation of propagation impairments. However, the actual commercial solutions for long-haul core/backbone networks are still complex and costly, and therefore hardly feasible for deployment in optical access networks. In particular, the main limitations arise from the customer premises equipment whose cost, footprint and power consumption may be kept down. Thus, the optimal solutions for next generation coherent optical access are required to achieve high performance but at lower complexity and cost, since in the access scenario the cost-effectiveness takes more relevance over achieving the best system performance.The research described in this thesis primarily aims at the development of the customer equipment ¿namely the coherent transceiver¿ for a passive optical access network that implements the novel wavelength-to-the-user concept by serving hundreds of users (e.g., 256 users) with dedicated wavelengths allocated in ultra-narrow optical grid. The proposed access network features complexity-reduced coherent technologies by leveraging photonic integration, commercial low-cost lasers and optics, and consumer electronics. To this end, the thesis investigates on the main transmission impairments that affect signal integrity from source to destination in the access network, and proposes novel and enhanced mitigation strategies by either low-complexity digital signal processing or analog hardware design.The covered topics spread over both the optical transmitter and the coherent receiver subsystems. Simplified optical modulation is addressed by direct phase modulation of semiconductor lasers profiting from the laser chirp. Digital pre-equalization of non-ideal frequency response from electronic/photonic devices ¿such as lasers, amplifiers and data converters¿ is investigated, focusing on the tolerance to quantization noise from digital-to-analog converters with limited resolution. Hardware-efficient strategies for optical carrier recovery based on differential phase detection are explored in two scenarios: homodyne receivers aided by digital signal processing, or fully analog heterodyne receivers. Finally, to deal with the critical polarization matching in coherent systems, simplified architectures for polarization-independent coherent receivers using low-cost optics and simpler receiver front-end are investigated.
  

Last update: 16/10/2021 05:11:51.

Research groups

• ANTENNALAB-Antennas and Wireless Systems Laboratory
• CommSensLab-UPC-Centre Especific de Recerca en Comunicacio i Deteccio UPC
• CSC-Components and Systems for Communications Research Group
• GCO-Optical Communications Group
• GPI-Image and Video Processing Group
• GRCM-Mobile Communication Reserach Group
• RF&MW-Laboratory of RF & microwave systems, devices and materials
• RSLAB-Remote Sensing Lab
• SPCOM-Signal Processing and Communications Group
• VEU-Speech Processing Group
• WiComTec-Wireless Communications and Technologies Research Group

Teachers

• Aguasca Sole, Alberto
• Agusti Comes, Ramon
• Alonso Zarate, Lluis
• Artigas Garcia, David
• Barlabe Dalmau, Antoni
• Belmonte Molina, Aniceto
• Bertran Alberti, Eduard
• Blanch Boris, Sebastián
• Broquetas Ibars, Antoni
• Cabrera Bean, Marga
• Camps Carmona, Adriano Jose
• Casadevall Palacio, Ferran
• Casas Pla, Josep Ramon
• Collado Gomez, J.Carlos
• Comellas Colome, Jaume
• Comeron Tejero, Adolfo
• Corbella Sanahuja, Ignasi
• Dios Otin, Victor Federico
• Duffo Ubeda, Nuria
• Fabregas Canovas, Francisco Javier
• Fernandez Rubio, Juan-Antonio
• Ferrus Ferre, Ramon
• Garcia Lozano, Mario
• Garcia Vizcaino, David
• Gasull Llampallas, Antoni
• Gelonch Bosch, Antoni
• Gene Bernaus, Joan M.
• Gilabert Pinal, Pere Lluis
• Giro Nieto, Xavier
• Gonzalez Arbesu, Jose Maria
• Heldring, Alexander
• Hernando Pericas, Francisco Javier
• Jofre Roca, Lluis
• Junyent Giralt, Gabriel
• Lagunas Hernandez, M. A.
• Lamarca Orozco, Meritxell
• Lazaro Villa, Jose Antonio
• Lopez Martinez, Carlos
• Mallorqui Franquet, Jordi Joan
• Marques Acosta, Ferran
• Mateu Mateu, Jordi
• Monte Moreno, Enric
• Montoro Lopez, Gabriel
• Moreno Bilbao, M. Asuncion
• Morros Rubio, Ramon
• Muñoz Medina, Olga
• Nadeu Camprubi, Climent
• Najar Marton, Montse
• O'callaghan Castella, Joan
• Olmos Bonafe, Juan Jose
• Pages Zamora, Alba
• Pardas Feliu, Montse
• Pascual Iserte, Antonio
• Perez Neira, Ana Isabel
• Perez Pueyo, Rosanna
• Perez Romero, Jordi
• Perez Torres, Juan
• Pradell Cara, Lluis
• Prat Goma, Josep
• Rey Micolau, Francesc
• Riba Sagarra, Jaume
• Rius Casals, Juan-Manuel
• roca cl,
• Rocadenbosch Burillo, Francisco
• Rodriguez Fonollosa, Javier
• Rodriguez Fonollosa, Jose Adrian
• Rodriguez Gomez, Alejandro
• Romeu Robert, Jordi
• Ruiz Boque, Silvia
• Ruiz Costa-Jussa, Marta
• Ruiz Hidalgo, Javier
• Ruiz Moreno, Sergio
• Sala Alvarez, Josep
• Salembier Clairon, Philippe
• Sallent Roig, Jose Oriol
• Santos Blanco, María
• Sicard, Michaël
• Soneira Ferrando, M. Jose
• Spadaro, Salvatore
• Tarres Ruiz, Francisco
• Torner Sabata, Lluis
• Torres Torres, Francesc
• Torres Urgell, Luis
• Ubeda Farre, Eduard
• Valenzuela Gonzalez, Jose Luis
• Vall-Llossera Ferran, Mercè
• Vazquez Grau, Gregori
• Vidal Manzano, Josep
• Vilaplana Besler, Veronica
• Villares Piera, Nemesio Javier