this is the first episode of our series 5g explained in this video we go over
the main goals and basic configuration of 5g new radio systems we will look at
use cases for v GN are requirements associated with the use cases some of
the main differences between v GN r and LTE and deployment scenarios that have
been envisioned by the 3gpp standardization body finally we'll touch
upon carrier frequencies for v GN r
let's talk about use cases first faggiano is not just a faster version of
LT this use case is called enhanced mobile broadband or e mb v and supports
higher data rates several other use cases have been defined massive machine
type communications or mmt C where a large number of devices are connected to
one base station and ultra reliable and low latency communications or URL LC
wear devices rely on very short latency to perform their task possible
applications include industrial automation virtual reality or some parts
of video X or car-to-car communications for autonomous driving to support this
use cases new requirements have been defined which enable fixed mobile
wireless and satellite access technology these include the ability to support a
large number of connected devices the round-trip latency of 1 millisecond for
URL LC cases increased bandwidth efficiency for all use cases ranging
from low to high bitrate requirements for energy efficiency and battery
powered optimization and lastly scalable and customizable networks in other
episodes of this 5g explained video series we will point out how some of the
physical layer features come in support of those requirements while there are
many commonalities we - in five GNR in LTE starting with the
names of most physical channels and signals there are also significant
differences between them this list is by no means exhaustive and there is more
discussion about this topic in other episodes of this 5g explain video series
nonetheless these seven points are quite fundamental to understanding how LTE and
5g annoy differ as already mentioned by GN is defined from the start to support
more use cases than LTE was initially conceived for and the latency
requirement is much more stringent this leads to several key changes in the
organization of a resource grid for v GN r carrier frequencies for 5g can be as
high as 60 or 70 gigahertz where LT is only deployed below 6 gigahertz here
again these are significant consequences on the design of the physical layer has
been forming becomes required to support those higher frequencies at those higher
frequencies more spectrum is available and v GN is set to take advantage of its
spectrum with up to 400 megahertz of bandwidth and possibly more later moving
on to more detailed points on the physical layer the subcarrier spacing
fixed in LT at 15 kilohertz can now take values between 15 and 240 kilo Hertz
regarding frequency allocation an LTE ue placed in a 20 megahertz cell is
required to decode the whole bandwidth and signals of interest can spanning the
whole bandwidth on the other hand 5g u YZ do not need to support the whole
bandwidth remember that the bandwidth in fact GN r can be much larger which would
have compounded that problem signals of interest can be confined to a subsection
of a bandwidth and bandwidth parts are one of the new concepts that help with
this capability finally the number of always-on signals has been reduced in 4G
on or in part to save energy the main casualty is the cell specific
reference signals or CRS which are provided in LTE as a cell wide reference
for demodulation in channel quality estimation CRS are no longer present in
5gn are another motivation for that change is that at higher carrier
frequencies signals need to be being formed in order to overcome propagation
losses as a result it is both difficult and not useful to provide cell wide
reference signals the signal strength will be too low and each channel is
being formed anyway which means that the UE
would need to be informed of the precoding matrix separately instead you
ease in 5g rely on reference signals that undergo the same beamforming as The
Associated channel possible deployment scenarios are listed in technical report
38.9 1-3 contrary to what people naturally think of when hearing about 5g
not all scenarios are high speed small cells as you can see here scenarios
range from indoor to rural with urban cells air-to-ground and connected cars
as potential applications here are a few example configurations from the
scenarios listed on the previous page when you look at the 38.9 1/3 document
you'll find antenna configurations up to seven hundreds of antennas and you may
notice bandwidth that are envisioned to exceed the capability of 400 megahertz
as defined in the current version of a standard also of interest to note is the
wide range of carrier frequencies from 700 megahertz all the way to 70
gigahertz the standard distinguishes between two different ranges for carrier
frequencies it calls them frequency range 1 and 2 or F R 1 and F R 2 those
two ranges correspond to very different propagation conditions and some physical
layer settings only apply to one of those modes this is the case of
subcarrier spacing as we will see in another
episode of his series this concludes this introduction to 5g the first part
of is 5g explained video series