School of Computer Science and Statistics
Dublin 2, Ireland
I'm a research fellow at Trinity College Dublin (Ireland) currently visiting YINS (Yale University, USA).
I obtained my degree in Telecommunications Engineering from Universitat Pompeu Fabra (Barcelona) in 2011, and MSc in 2012. In 2012, I started my PhD in applied mathematics at Trinity College Dublin under the supervision of Prof. Doug Leith, which I've recently completed (May 2017).
During the second half of 2015 I visited the NEC Laboratories in Heidelberg (Germany), where I worked on the coexistence of unlicensed LTE and WiFi in 5G networks.
My research interests are in the area of mathematical optimisation with applications in communication networks, decision and control systems, large-scale distributed algorithms and statistical learning.
Preprints / Submitted
V. Valls and D. J. Leith, "Max-weight revisited: Sequences of nonconvex optimizations solving convex optimizations," in IEEE/ACM Transactions on Networking, vol. 24, no. 5, pp. 2676-2689, Oct. 2016.
V. Valls and D. J. Leith, "Proportional fair MU-MIMO in 802.11 WLANs," in IEEE Wireless Communications Letters, vol. 3, no. 2, pp. 221-224, April 2014.
R. Liao, B. Bellalta, J. Barcelo, V. Valls and M. Oliver, "Performance analysis of IEEE 802.11 ac wireless backhaul networks in saturated conditions," in EURASIP Journal on Wireless Communications and Networking, pp. 226, 2013.
V. Valls, J.L. Sánchez, C. Cano, B. Bellalta and M. Oliver, "Hierarchical range sectoring and bidirectional link quality estimation for on-demand collections in WSNs," in Ad Hoc Networks, vol. 11, no. 3, pp. 894-906, May 2013.
V. Valls and D. J. Leith, "Subgradient methods with perturbations in network problems," 54th Annual Allerton Conference on Communication, Control, and Computing (Allerton), Monticello, IL, 2016, (accepted)
V. Valls, J. Monteil and M. Bouroche, "A convex optimisation approach to traffic signal control," 2016 IEEE 19th International Conference on Intelligent Transportation Systems (ITSC), Rio de Janeiro, Brazil, 2016, pp. 1508-1515.
V. Valls and D. J. Leith, "Stochastic subgradient methods with approximate Lagrange multipliers," 2016 IEEE 55th Conference on Decision and Control (CDC), Las Vegas, NV, USA, 2016, pp. 6186-6191.
V. Valls and D. J. Leith, "Dual subgradient methods using approximate multipliers," 53rd Annual Allerton Conference on Communication, Control, and Computing (Allerton), Monticello, IL, 2015, pp. 1016-1021.
V. Valls and D. J. Leith, "On the relationship between max-weight scheduling and dual subgradient methods," in AIRO Winter Conference, January 2015.
V. Valls and D. J. Leith, "On the relationship between queues and multipliers," 52nd Annual Allerton Conference on Communication, Control, and Computing (Allerton), Monticello, IL, 2014, pp. 250-255.
M. Oliver, M. Palacín, A. Domingo and V. Valls, "Sensor information fueling open data," in Computer Software and Applications Conference Workshops (COMPSACW), 2012 IEEE 36th Annual, Izmir, 2012, pp. 116-121.
Theses, Patents and Technical Reports
- V. Valls and D. J. Leith, "Descent with approximate multipliers is enough: Generalising max-weight," Technical Report. November 2015.
V. Valls, "A Convex Optimisation Approach to Optimal Control in Queueing Systems", PhD Thesis, Trinity College Dublin, 2016 (supervised by Prof. Douglas Leith)
V. Valls, "Multi-User Beamforming with Explicit Channel Sounding and Proportional Fairness Scheduling in IEEE 802.11ac", MSc Thesis, Universitat Pompeu Fabra and Universitat de Valencia, 2012 (supervised by Dr. Boris Bellalta and Prof. Douglas Leith)
V. Valls, A. Garcia-Saavedra, X. Costa Pérez, "Channel access mechanism for LTE networks coexisting with WiFi networks in unlicensed bands", Patent application PCT/EP 2016/052425