NYU WIRELESS, Summer 2013: 73 GHz Ultra-Wideband Propagation  Measurement Campaign in New York City

Wireless communications has
fundamentally revolutionized the way we live and conduct business in today’s
world as smartphones and tablets and machine-to-machine all skyrocket in
popularity and as customers continue to demand greater and greater data rates to
their mobile device every cellular provider around the world will continue
to face the Paramount problem of bandwidth shortage New York City the world’s toughest urban
environment to conduct propagation measurements this is where NYU Wireless
a new world class research center at nyu-poly in partnership with the quran
institute and the nyu langone medical center is conducting one of the world’s
greatest wideband propagation measurement campaigns to study the
seventy three gigahertz propagation channel for the fifth generation
cellular backhaul technology using a broadband spread spectrum sliding
correlator channel sounder this measurement campaign will allow us to
create statistical spatial channel models to help with future base station
deployment for this campaign a 400 mega chip per second sudo Norris random
sequence is generated with a 400 megahertz clock produced with the
National Instruments pxi 5652 RF signal generator the intermediate frequency is
obtained by mixing the baseband signal with a 5.6 gigahertz signal and the RF
signal is obtained by mixing the intermediate frequency with a local
oscillator frequency of 22.6 gigahertz the if’ and ello frequencies are
obtained with two quick sand signal generators and a frequency doubler
provided by phase matrix a subsidiary of National Instruments the Ehlo is further
frequency tripled to sixty seven point nine gigahertz before mixing with the
if’ via this basic labs up converter in order to transmit at 73.5 gigahertz with
a 27 d bi-directional horn antenna the signal is then propagated through the
wireless channel and experiences attenuation from free space propagation
reflections penetrations and diffraction around building corners the signal is
picked up via a receive antenna of 27 DB I and the spacek lab is down converter
which are both located 15 feet above the ground on top of 15 feet high mast the
receive antenna is exhaustively rotated in the elevation and azimuth planes and
10 degree increments to recover multipath components arriving from all
possible incoming directions once the RF signal is captured it is down converted
to i.f and baseband via two-phase matrix quicksand signal generators and a
frequency doubler the baseband pn signal is correlated with an identical version
of itself clocked at a slightly lower speed via the national
struments pxi 5652 signal generator providing a slide factor of eight
thousand and a multi-path time resolution of 2.3 nanoseconds and the
signal is sampled with the national instrument data acquisition USB 5133
digitizer at each azimuthal elevation angle combination a power delay profile
is recorded in LabVIEW and the data is saved as a comma separated document for
later post-processing we have found a path loss exponent with respect to a
formula free space reference distance of 4.7 for when considering all possible
receiver azimuth angles and 3.2 one when considering just the strongest
transmitter to receiver link at each receiver location these path loss
exponent SAR very comparable to those involved in today’s 3G and 4G systems
beamforming algorithms and electrically steer down chip antenna arrays will be
able to combine energy arriving from the strongest incoming directions at the
receiver this polar plot shows the azimuthal distribution of total received
power and an on line of sight environment this power delay profile
clearly identifies four strong multipath components picked up at the receiver
antenna at a particular receiver as a youth angle the advantages of using
National Instruments hardware is that it is compact of small form factor and
light to move around key elements for a successful outdoor measurement campaign understanding the channel allows
researchers and engineers to then begin building the infrastructure to provide
multi gigabit per second data rates to mobile phones in urban environments
using highly directional steerable antennas NYU Wireless researchers at NYU
and nyu-poly are leading the way in this new future is in a very exciting future you

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