By Paul Pickering, Technical Contributor
Figure 1: 5G can’t come too soon for the video industry.
(Image Source: Ericsson traffic measurements Q4 2017)
In 2017, the global population was 7.56 billion. However, according to the latest Ericsson Mobility
Report, there were around 7. 8 billion mobile
subscriptions at the end of 2017, for a penetration rate
of 103 percent. Of those, 5. 2 billion are broadband
subscriptions. Unsurprisingly, mobile data traffic
dwarfs voice traffic, driven primarily by more video
content viewed at higher resolutions—by 2021, video
is forecasted to constitute 75 percent of data usage. It
looks like 5G, the fifth generation of wireless standards,
will arrive in the nick of time.
Compared to 4G, 5G aims for a 10X decrease in end-to-end latency, 100X traffic capacity and network efficiency,
three times the spectrum efficiency, and 10 times the
connection density. 5G will include both mobile and
fixed-base wireless applications; for example, a 5G modem
can replace fiber-to-the-home (FTTH) installations with
5G’s increased performance will spawn a slew of new
services over the next few years. Video streaming, for
example, will add ultra-high-definition (4K, 8K) and 3D
video, along with virtual reality. Ultra-high-fidelity virtual
reality can consume 50 times the bandwidth of an HD
video stream. The Internet of Things (Io T) will be able
to add real-time interactivity to applications ranging from
remote inspection and maintenance, to robotic surgery.
Of course, let’s not forget the coming automotive “Brave
New World” of autonomous vehicles, advanced driver-assistance systems (ADAS), vehicle-to-vehicle (V2V)
communications, and more.
5G NR: The First Wave
3GPP, the organization that set standards for earlier
wireless network technologies, approved Release 15 in late-
2017: this standard will pave the way for transitions from
4G LTE to 5G New Radio (NR)—the first global standard
for fifth-generation networks. It defines waveforms,
channel coding and modulation schemes, plus advanced
antenna techniques that open up new frequency bands
previously unusable by mobile networks.
The 5G NR specification covers three frequency ranges:
low-band (below 1 GHz); mid-band (1 GHz to 6 GHz);
and high-band (above 24 GHz), known as mm Wave.
The initial deployments will concentrate on the low and
mid bands. The 3GPP standard defines non-standalone
(NSA) and standalone (SA) standards: NSA is intended to
support connection with older LTE towers, and SA covers
newer 5G networks built solely with 5G infrastructure.
Massive MIMO antennas are a key 5G requirement.
MIMO stands for multiple-input, multiple-output: a
MIMO installation increases the number of antennas on a
radio, and can simultaneously accommodate multiple users.
Compared to single-antenna systems, a MIMO system
improves spectral efficiency—the useful information rate
that can be transmitted over a given bandwidth in a specific
communication system, measured in bits/sec/Hz.
The MIMO concept has been around for a while; WiFi
and LTE networks both use MIMO antennas.
“Massive” has no number attached, and merely means
“many more than are currently used.” In practice, base
stations in 5G may well have arrays of 128 or 256 mini-antennas, and 5G devices (e.g., tablets or smartphones) will
have between two and 10 mini-antennas.
The signal from each transmitting antenna in the MIMO
array is reflected off various obstacles before it reaches the
receiver. The receiver, therefore, sees a multipath signal
with several versions of the transmission, each one with
its own delay, attenuation, and direction. Each version can
be used to improve quality of the received signal if the
system corrects for the spatial environment between each
transmitter antenna and the receiver.
This spatial characterization is typically performed by the
base station, which analyzes an uplink pilot signal sent from
the device; the channel state information (CSI) matrix thus
formed is used to “precode” the data before transmission,
so that the multipath signal is coherently received at the