October 2015
37
E
mbedded
W
ireless
LTE and optimizing LTE Advanced
for machine-type communications
By Felix Marchal,
Telit
LTE differs from earlier networks
with brand-new network core and
air interface technologies providing a
groundbreaking combination of effi-
ciency and flexibility. The efficient use
of spectrum will lead to lower costs
and the ability to combine high-speed,
low-latency transmission with
cost-effective, low bit rate services.
LTE-A offers a high data rate of
300 Mbps or more and
high-mobility performance.
LTE-MTC (also known as LTE-M) is a con-
venient way of encapsulating the optimization
of LTE Advanced for machine-type communi-
cations. LTE is marketed as 4G: marketed that
way because technically it’s 3.9G. LTE-Ad-
vanced (LTE-A) is the real 4G because it meets
the ITUs requirements for fourth-generation
wireless systems. Cellular networks have tran-
sitioned from circuit-switched 2G through to
packet-switched 3G, 3.5G (HSPDA) and 3.75
G (HSPDA +), but 4G represents a quantum
step. It involves next-generation technology
like OFDM (Orthogonal Frequency Division
Multiplexing) in the air interface and a sim-
plified, flat, all-IP architecture having open
interfaces and an Evolved Packet Core (EPC).
OFDM is immune to selective fading, resil-
ient to interference, and it makes efficient
use of the available spectrum. LTE / 4G net-
works can therefore accommodate up to 10
times more traffic than earlier generations. In
addition LTE supports IPv6, which expands
the addressable IP space to an inexhaustible
figure. LTE employs UE (User Equipment)
categories to define the performance specifi-
cation: the higher the category, the higher the
data rate. Category 0 download data rate is 1
Mbps; Category 1 download data rate is 10
Mbps; Cat 6 is 300 Mbps; LTE-A Cat 8 is set
to reach3 Gbps. Higher categories are driven
by consumer applications. A data rate of 1
Mbps is more than adequate for most M2M
applications, so why mention these higher fig-
ures? Two reasons: one, they indicate that LTE
is intrinsically flexible and two; they demon-
strate that development work is ongoing.
LTE has followed a well thought-out roadmap
with releases providing successively improv-
ing capabilities that result in: higher and more
consistent data rates for users; higher capac-
ity; and a better overall user experience. It is
set to become a common technology standard
that will enable economies of scale and have a
significant impact on our personal and busi-
ness lives. Moreover, it’s a ubiquitous com-
munications technology that can deliver the
connectivity requirements of the upcoming
IoT era. LTE is ideal for IoT applications that
need to respond in real-time, e.g. controlling
sensitive equipment, critical smart-grid apps,
industrial alarm systems, traffic control sys-
tems, and medical devices. The low latency of
LTE can enable connected applications that
would not otherwise be possible. LTE net-
works were designed to fall back to an ear-
lier generation network if the attached device
could not detect a 4G signal. This was an early,
mandatory requirement since different coun-
tries had different rollout timing and coverage
plans. In addition fallback is important since
it allows companies to future-proof their solu-
tions. Companies who recognize that LTE
technology will be the global standard and
who are marketing solutions that have long
life times, ten years or more in key segments
like automotive, cannot rely on 3G since it too
might reach decommissioning status within
this timeframe.
LTE is the first network technology that can
comfortably accommodate demanding appli-
cations like real-time video surveillance and
at the same time provide cost-effective con-
nectivity for low-speed applications. There-
fore although these apps have widely different
performance requirements, the market will be
able to build a wide-ranging ecosystem on a
single, wide area communication technology.
Moreover, LTE has or will have everything
going for it: superior performance; ubiqui-
tous connectivity; scalability; low cost per bit,
delivery of whatever QoS customers require,
and longevity (MNOs are or will be retiring
older network types).
LTE MTC is part of Release 13 of the global
3GPP standard, which is planned for March
2016. The benefits include: leveraging the
reliability, pervasiveness, efficiency and lon-
gevity of 4G LTE, the significant increase
in battery life thanks to longer sleep cycles,
while reducing cost/complexity and enhanc-
ing coverage in what have traditionally been
difficult-to-reach locations, such as inside
