Aerospace and Electronic Systems Magazine May 2018 - 69

Kumar and Prasad

Figure 3.

User accumulation affecting signal coverage in the affected area.

locations across the network area. Therefore, the portion of the
network area falling in open land where no households exist may
be planned with very low network site density, although on some
occasions, the same area may be packed with people attending festivals or lives shows, etc. As a result, an NSP may face a steep
rise in customer dissatisfactions when the network is exposed to
unprecedented circumstances such as these.

PTC2 Impact on the Single Network Phase
The PTC2 problem has been prevailing since the beginning of
mobile wireless communications, in particular with those having
cellular structure. This is because cellular mobile communications
have spectrum constraints and therefore cannot have an indefinite
number of sites in any given area. Still, the first generations of
networks were not much affected by PTC2 due to the minuscule
subscriber base, lower network penetration and, lower bit rate, and
therefore, gained less attention from NSPs. However, for future
radio communications such as 5G [8] and [9], the PTC2 is going
to put a lot of resistance against the smooth network operations.

PTC2 Impact when NSPs are Catering to Multiple Technologies
in the Same Network
Every NSP undergoes a technological transition from time to time.
There are service providers around the globe that have all three
generations, second (2G), third (3G), and fourth (4G) operating
in the same geographical area. In such a case, user accumulations,
as shown in Figure 2, can affect multiple generations at the same
time, proving to be very devastating.
Figure 4a shows a Cell on Wheels (CoW) site that is part of a
mobile infrastructure and is used as a temporary solution for regular and known accumulations, such as a fete shown in the Figure
4b. These kinds of solutions are typical in practice by NSPs to
avoid the cost of permanent architecture. From Figures 4a and
4b, it can be realised that NSPs are trying to reinvent the network
infrastructure to accommodate the PTC2 wobbles on a miniature
MAY - JUNE 2018

level. Despite this effort, such solutions are not very effective in
addressing sporadic PTC2 problems.

PLACE TIME RESPONSIVE NETWORK
In this section, we suggest solutions that could mitigate the PTC2
problem described in the previous section and explain how this
architecture will reduce the PTC2 challenge.

SCIDAS: THE PROPOSED ARCHITECTURE
In our previous work [5], we introduced and defined an architecture called the Self Configurable Intelligent Distributed Antenna
System (SCIDAS), which we believe can handle the PTC2 situation
very well. This design takes advantage of conventional distributed
antenna system (DAS) methodology with the overlay of intelligent
sub-architecture.

Inheriting from the Conventional Distributed Antenna System
Figure 5 shows a simple DAS network, where the resources of
a BS are distributed across a larger area, reducing the need for
additional BSs. As shown in Figure 5, the BS interfaces with the
Optical Master Unit (OMU), which modulates the radio frequencies over the optical carrier, which then propagates through the
optical fibre network (OFN) to reach various remote sites. At each
remote site, there is an Optical Remote Unit (ORU), which eventually demodulates the optical signal to radio frequencies and feeds
them to the local antenna for service in the surrounding area. This
moves beyond the need for the physical presence of the BS at every location, as compared to the conventional approach, as shown
in Figure 2, where the BS is collocated at every site location. The
DAS methodology is currently used in some advanced architectures, such as the cloud-radio access network, where a group of
BSs are colocated in what is known as a BS-hub and resources are
distributed from there to the larger area.

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Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine May 2018