Creating and sharing knowledge for telecommunications

Multi-Beam Power Allocation for MillimeterWave Communications under Random Blockage

on 07-06-2018

... Sungoh Kwon, Ulsan University, Republic of Korea

Date & Time: Thursday, June 7, 16:00
Location: Instituto Superior Técnico, Lisbon, Abreu Faro Amphitheatre, Interdisciplinary Building

Milimeter-wave links can provide Gbit/s data rates but are highly susceptible to blockage. In case a direct line-of-sight communication path becomes blocked, communication via a reflected path may allow to maintain connectivity. A common approach is to switch to such an alternative path whenever the first path becomes blocked. However, this requires detecting the blockage and then reconfiguring the transceiver to use the new path, which incurs latency. For traffic with strict latency or reliability requirements, or in highly dynamic environments where path switching would be frequent, using both paths concurrently can be more beneficial. In this work, we consider using multiple paths and dividing the transmission power over those paths, instead of path switching. We propose an algorithm to allocate power among the different mmWave communication paths to overcome link blockage under randomly distributed obstacles. The power allocation algorithm is based on analysis of the blockage probabilities of the direct and reflected paths using geometric probability, to statistically maximize the overall capacity of the path between two nodes. We evaluate the performance of the proposed algorithm via simulation for various wireless environments. More Information..

Engineering Quantum Causes

on 17-05-2018

... Gerard Milburn, from the University of Queensland and Imperial College

Date & time: Thursday, May 17th, 17:00h
Location: Instituto Superior Técnico, Lisbon, Abreu Faro Amphitheatre, Interdisciplinary Building

Are cause and effect objective facts about the world? Many philosophers doubt it. Physicists ground causation objectively in terms of Lorentz invariance: a central feature of quantum field theory. Yet the pioneers of quantum mechanics lamented the demise of classical causality and the violation of various Bell-like inequalities raise new questions. Nonetheless,
advancing quantum communication technologies seek to exploit non classical quantum correlations to perform tasks impossible in a classical world. Quantum information theorists have recently discovered new quantum causal relations beyond Bell, yet the physical meaning of this discovery remains unclear. In this talk I will review some of the recent theories on classical and quantum causation and explain how ion trap quantum technologies might be used to engineer novel causal relations in a laboratory setting. More Information..