To fulfil all these ambitions demands al-
most infinite flexibility, so 5G is incred-
ibly complex; much more so even than
3G and 4G. It has taken a long time for
the standards bodies to define the spec-
ifications adequately for trials to begin,
and work on some of the more complex
features has not yet begun. Only when
these are ready can companies proper-
ly tackle the challenges associated with
designing, building, and testing infra-
structure equipment and networks.Specifications still open
To get 5G up and running, and into the
public consciousness, the pilot services
rolling out this year are Non-Standalone(NSA) implementations. While 5G fre-
quencies will be used for high-speed
data exchanges, the networks will rely
on 4G (LTE) technologies to manage
connections to infrastructure and serv-
ers. The 3GPP TS38.521-3 transmitter
and receiver tests for interworking with
LTE in the 5G Frequency Range 1 (FR1)
below 6GHz and in the FR2 mm-wave
bands (24GHz-52GHz) are quite well
developed. On the other hand, per-
formance tests (38.521-4) and radio
resource management (RRM) test re-
quirements have been standardised but
various points remain open and need to
be clarified.Corresponding specifications for stan-
dalone (SA) operation, namely TS38.521-
1 for FR1 and TS38.521-2 for FR2 are
more advanced, although other parts of
the SA standards will not be approved
until later this year.New approaches to testing
Although the standards bodies are work-
ing as quickly as possible to complete the
test specifications, the risk of compatibili-
ty or performance issues can be problem-
atic for companies developing products
or services to use 5G networks.There are many technical challenges,
too. For instance, the beamforming
active antenna systems of 5G radio de-
vices demand new test techniques and
equipment. PCBs comprising antennas,
amplifiers and analog phase shifters
must be highly integrated to minimise
internal attenuation, but suitable RF
connectors for making traditional con-
ducted measurements are not available.
Instead, testing must be done Over the
Air (OTA).OTA testing places constraints on
the distance between the device un-
der test (DUT) and the antenna of theFeature: What is 5G?
C
ommercial 5G trials are beginning this year
and, with discussions about the companies
bidding for infrastructure contracts now hitting
the news, many people will surely ask “What is
5G?” Of course, 5G is so much more than simply
the successor to 4G. In fact, it seems that 5G is
expected to be everything to everybody – the go-to
consumer broadband technology, the connectivity
for autonomous motoring, the channel for masses
of IoT data, the medium for smart manufacturing
and Industry 4.0. And that’s just for starters.dpaonthenet.net 15
5G’s far-reaching ambitions set
complex and long-term challenges