MIMO channel measurement campaign in subway tunnels

Abstract—The recent construction of the new L9 subway line in Barcelona, Spain has provided the opportunity to study the impact of different antenna configurations on the maximum channel capacity inside subway tunnels. In this work the authors present the design tradeoffs inside different kind of tunnels in terms of antenna spacing and applied diversity technique for a 2x2 MIMO system at C-Band. These design tradeoffs are the conclusion of the measurement campaign carried out during last year at L9 subway tunnels.Peer ReviewedPostprint (published version

Multiple element antenna placement and structure studies in subway environments

Public subway transport networks require reliable high data reate wireless communication systems. One way to increase the maximum theoretical capacity in a certain environment is to apply the known MIMO techniques in order to maximize the presence of orthogonal sub-channels in a certain radio-channel. In this work the authors present a method to assess the impact of the position inside the tunnel and the diversity configuration of the antennas of the considered MIMO system on the maximum theoretical capacity of the radio-channel inside subway tunnels.Peer ReviewedPostprint (published version

Small UAV radiocommunication channel characterization

Small Unmanned Aerial Vehicles (UAV) are finding different applications as platforms to carry observation payloads. The need to establish reliable high data rate channels requires to characterize the radiocommunication channel between the UAV and the ground station. In this communication an experimental set-up and some results for the characterization of a radio channel at 5.8 GHz are presented.Postprint (published version

M.I.M.O Channel Model for High Capacity Wireless Networks and Simulator for Performance Analysis Bachelor thesis performed in Electronics Systems Channel Model for High Capacity Wireless Networks and Simulator for Performance Analysis Serietitel och serie

Abstract The wireless communications have suffered, in these last years, one of the greater technological growth within the communications via radio. The application of multiple antennas, as much in transmission as in reception has taken to an impulse of the study of different models from propagation channels. Taking this into consideration, the different types from mentioned models are going to be studied. The work that the ISY department at the Institute of Technology of the Linköping University has proposed is to develop to a propagation channel model, with several antennas in reception and transmission, that one first approach allows a capacity of the channel study, in absence of measures of possible scenarios, as well as the development of a small simulator that allows to analyze its benefits. ABSTRACT The wireless communications have suffered, in these last years, one of the greater technological growth within the communications via radio. The application of multiple antennas, as much in transmission as in reception has taken to an impulse of the study of different models from propagation channels. Taking this into consideration, the different types from mentioned models are going to be studied. The work that the ISY department at the Institute of Technology of the Linköping University has proposed is to develop to a propagation channel model, with several antennas in reception and transmission, that one first approach allows a capacity of the channel study, in absence of measures of possible scenarios, as well as the development of a small simulator that allows to analyze its benefits. ACKNOWLEDGEMENTS English After many years of study, finally, I finish here in Sweden which began when I was young in a school of Madrid. I would like, in these lines, to thank for all the people who have made this adventure possible. I will begin by my parents and my brother, whose continuous effort in doing a person to me of good I have had all the opportunities that the life has offered me. To Beatriz to be next to me, so far and so close, in this final straight line of the race, and all the friends from Madrid who have contributed to their patience and their friendship at the best moments of my life. To thank for the people who have made my stay in this wonderful place possible during the last year. To thank for the Alcalá and Linköping universities, Antonio Guerrero and mainly, Kent Palmkvist had offered me this opportunity and had been patient with me and my work. Also to the university mates who animated, supported and shared with me in long days of study, to all of them, as much first as to the seconds. Spanish Después de muchos años de estudio, finalmente, termino aquí en Suecia lo que empezó cuando era niño en un colegio de Madrid. Me gustaría en estas líneas agradecer a todas las personas que han hecho posible esta aventura. Empezaré por mis padres y a mi hermano, a cuyo esfuerzo continuo en hacerme una persona de bien le debo todas las oportunidades que me ha brindado la vida. A Beatriz por estar junto a mí, tan lejos y tan cerca, en esta recta final de la carrera y todos los amigos de Madrid que han aportado su paciencia y su amistad a los mejores momentos de mi vida. Agradecer a la gente que ha hecho posible mi estancia en este maravilloso lugar durante el último año. A las universidades de Alcalá y Linköping, a Antonio Guerrero y, sobre todo, a Kent Palmkvist por ofrecerme esta oportunidad y por su paciencia conmigo y mi forma de trabajar. También a los compañeros de la universidad que me animaron, apoyaron y compartieron conmigo los largos días de estudio, a todos ellos, tanto los primeros como a los segundos. Por último, dar gracias por este año de vivencias, aventuras, estudio y amistad. Recordar que este ha sido uno de los mejores años de mi vida, no sólo por el lugar donde he estado trabajando, sino por la gente que aquí he conocido, europeos y españoles

Multiple element antenna placement and structure studies in subway environments

Public subway transport networks require reliable high data reate wireless communication systems. One way to increase the maximum theoretical capacity in a certain environment is to apply the known MIMO techniques in order to maximize the presence of orthogonal sub-channels in a certain radio-channel. In this work the authors present a method to assess the impact of the position inside the tunnel and the diversity configuration of the antennas of the considered MIMO system on the maximum theoretical capacity of the radio-channel inside subway tunnels.Peer Reviewe

MIMO channel measurement campaign in subway tunnels

Abstract—The recent construction of the new L9 subway line in Barcelona, Spain has provided the opportunity to study the impact of different antenna configurations on the maximum channel capacity inside subway tunnels. In this work the authors present the design tradeoffs inside different kind of tunnels in terms of antenna spacing and applied diversity technique for a 2x2 MIMO system at C-Band. These design tradeoffs are the conclusion of the measurement campaign carried out during last year at L9 subway tunnels.Peer Reviewe

Multiple element antenna placement and structure studies in subway environments

Public subway transport networks require reliable high data reate wireless communication systems. One way to increase the maximum theoretical capacity in a certain environment is to apply the known MIMO techniques in order to maximize the presence of orthogonal sub-channels in a certain radio-channel. In this work the authors present a method to assess the impact of the position inside the tunnel and the diversity configuration of the antennas of the considered MIMO system on the maximum theoretical capacity of the radio-channel inside subway tunnels.Peer Reviewe

MIMO channel measurement campaign in subway tunnels

Abstract—The recent construction of the new L9 subway line in Barcelona, Spain has provided the opportunity to study the impact of different antenna configurations on the maximum channel capacity inside subway tunnels. In this work the authors present the design tradeoffs inside different kind of tunnels in terms of antenna spacing and applied diversity technique for a 2x2 MIMO system at C-Band. These design tradeoffs are the conclusion of the measurement campaign carried out during last year at L9 subway tunnels.Peer Reviewe

Electrical detection of ortho-para conversion in fullerene-encapsulated water

Water exists in two spin isomers, ortho and para, that have different nuclear spin states. In bulk water, rapid proton exchange and hindered molecular rotation obscure the direct observation of two spin isomers. The supramolecular endofullerene H2O@C60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show that the bulk dielectric constant of this substance depends on the ortho/para ratio, and changes slowly in time after a sudden temperature jump, due to nuclear spin conversion. The attribution of the effect to ortho–para conversion is validated by comparison with nuclear magnetic resonance and quantum theory. The change in dielectric constant is consistent with an electric dipole moment of 0.51±0.05?Debye for an encapsulated water molecule, indicating the partial shielding of the water dipole by the encapsulating cage. The dependence of bulk dielectric constant on nuclear spin isomer composition appears to be a previously unreported physical phenomeno

Testing signal enhancement mechanisms in the dissolution NMR of acetone

In cryogenic dissolution NMR experiments, a substance of interest is allowed to rest in a strong magnetic field at cryogenic temperature, before dissolving the substance in a warm solvent, transferring it to a high-resolution NMR spectrometer, and observing the solution-state NMR spectrum. In some cases, negative enhancements of the 13C NMR signals are observed, which have been attributed to quantum-rotor-induced polarization. We show that in the case of acetone (propan-2-one) the negative signal enhancements of the methyl 13C sites may be understood by invoking conventional cross-relaxation within the methyl groups. The 1H nuclei acquire a relative large net polarization through thermal equilibration in a magnetic field at low temperature, facilitated by the methyl rotation which acts as a relaxation sink; after dissolution, the 1H magnetization slowly returns to thermal equilibrium at high temperature, in part by cross-relaxation processes, which induce a transient negative polarization of nearby 13C nuclei. We provide evidence for this mechanism experimentally and theoretically by saturating the 1H magnetization using a radiofrequency field pulse sequence before dissolution and comparing the 13C magnetization evolution after dissolution with the results obtained from a conventional 1H-13C cross relaxation model of the CH3 moieties in acetone