May 01, 2018

Over-The-air tests of high-speed moving LTE users in a reverberation chamber

© 1967-2012 IEEE. High-speed trains are nowadays a reality in most of the countries. Internet services and connectivity are required by the passengers on board using smartphones and laptops. Nevertheless, the higher the speed, the bigger the issues that operators have to face to implement mobility and to reduce the effect of fast fading signal and Doppler shift, which may cause throughput reduction and problems to access the network. In the past, operators tried to optimize the cellular access to universal mobile telecommunications system cells covering railways. Now that 4G networks have become mature and deployed, a similar approach needs to be optimized and implemented to long-term evolution cells covering the same targets. We present the results of a testing campaign replicating real 'high-speed train' propagation scenarios, like a train running in open space or in tunnels with the help of a reverberation chamber. The chamber was partially filled by absorbing panels and equipped with rotating stirrers in order to approach the multipath propagation and to replicate the fading conditions that is typical of smartphones in a train coach. The effects of Doppler and its fast variations are presented, together with an analysis of the efficiency of different transmission solutions for tunnels (single-input single-output cells propagating inside them). The testing sessions were performed under a collaboration program between Telecom Italia (in the paper referred as 'operator'), Nokia Networks, and Università Politecnica delle Marche. After the experiments in our laboratory, some features were introduced in the operator's live network, covering the high-speed railway between the two Italian cities of Piacenza and Bologna.

View Original Article

Recent Publications

August 01, 2019

Protecting photonic quantum states using topology

  • Blanco-Redondo A.

The use of topology to protect quantum information is well-known to the condensed-matter community and, indeed, topological quantum computing is a bursting field of research and one of the competing avenues to demonstrate that quantum computers can complete certain problems that classical computers cannot. In photonics, however, we are only ...

May 01, 2019

Digital networks at the nexus of productivity growth

  • Kamat S.
  • Prakash S.
  • Saniee I.
  • Weldon M.

This paper takes a fresh look at the debate over the relationship between digital technology and productivity. The argument of economic historian Robert J. Gordon is that digital technology will not lead to increases in productivity such as we saw in the last century, based on his analysis of the ...

January 01, 2019

Friendly, appealing or both? Characterising user experience in sponsored search landing pages

  • Bron M.
  • Chute M.
  • Evans H.
  • Lalmas M.
  • Redi M.
  • Silvestri F.

© 2017 International World Wide Web Conference Committee (IW3C2), published under Creative Commons CC BY 4.0 License. Many of today's websites have recognised the importance of mobile friendly pages to keep users engaged and to provide a satisfying user experience. However, next to the experience provided by the sites themselves, ...