IEEE Consumer Electronics Magazine - April 2017 - 28

MSC
BSC

MSC
BSC

BS

BSC

BS

BS

BS

BSC

BS
BS
BS

BS

BS

BS

BS

BS
FIGURE 1. The traditional architecture of 1G-4G wireless systems.

Beamforming Links

mm AN

mm AN

Beamforming Links

BS

FEMTO

BS

mm AN
FEMTO
BS

mm AN
Beamforming
Links

FEMTO

mm AN

mm AN

FIGURE 2. The heterogeneous UDN architecture for 5G systems.

connectivity of not only people but also
anything, (e.g., an oven that needs to be
monitored and turned on or off remotely).
This means that future wireless systems
need to address the problem of explosive
growth of network traffic with enhanced
real-time performance in a cost-effective
way. As indicated by Agiwal et al. [12],
a summative view of various research
initiatives from academia and industry
aimed at meeting the aforementioned
overarching goal yields the following
eight subgoals for 5G systems:
1) 1-10-Gb/s data rates, i.e., an over
tenfold increase from traditional LTE
network peak data rates
2) 1-ms network round-trip latency,
i.e., a tenfold reduction from the
current 4G network latency
28 IEEE Consumer Electronics Magazine

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april 2017

3) a higher bandwidth in unit area so
that a large number of devices with
high-bandwidth requirements remain
connected in any area for a long time
4) an enormous number of connected
devices to make IoT and IoV feasible
5) a 99.999% perceived availability
to ensure that the network is always available
6) a nearly 100% coverage for anywhere anytime connectivity
7) a 90% reduction in energy usage
8) a high battery life.

ARCHITECTURAL INNOVATION
AND ENABLING TECHNOLOGIES
FOR 5G WIRELESS
The traditional architecture of the 1G
through 4G wireless networks is shown in

Figure 1. Each cellular (hexagonal-shaped)
geographical location is covered by a base
station (BS) that communicates with user
equipment (e.g., a mobile phone) by sending and receiving signals through cell
towers. A number of BSs are under the
control of a base station controller (BSC).
Some of the BSCs are under the control of
a mobile switching center (MSC), which
continuously keeps track of the position of
the user using two databases called the
home location register and the variable location register.
When a local user tries to call a remote
user, a call is set up by an exchange of the
call setup signals between the user along
the forward and reverse paths depicted in
Figure 1. Once the call is set up, the voice
or data call between the users will take
place along identical paths, though the
local and remote BS, BSC, and MSC
nodes change dynamically depending
upon the mobility of the two users.
In the event that a mobile phone
moves away from an area covered by a
BS into that covered by another BS, the
control is passed on from the former BS
to the latter by means of a mechanism
called handoff or handover that uses relative strengths of the signal received at the
two nodes to make the control transfer
decision. BSs provide the users access to
the infrastructural network and are also
called access nodes (ANs).
This traditional architecture does not
meet the 5G requirement that an enormous number of devices with high-bandwidth requirements remain connected in
any area for a long time because every
cellular area is covered by only a single
AN, and it can support only a few carrier
frequencies (and hence users). The 5G
wireless researchers propose to address
this limitation by a paradigm shift from
AN-centric architecture to user-centric
architecture (see Figure 2). This architecture is based on the idea that equipping
every user/device with a personal BS (or
AN) is a way of fulfilling the vision [13]
of all time connectivity everywhere
without compromising on quality or
user requirements.
In this novel heterogeneous ultradense
network (UDN) architecture, traffic in
hotspot localized areas is offloaded with
smaller footprint cells within macrocell
Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - April 2017
