Network Design Considerations

“3G System RF Design Considerations,” addressed the RF design
issues related to the implementation of a 3G network. This chapter focuses
on the design of the non-RF aspects of the network.Thus, we consider issues
such as placement and dimensioning of Mobile Switching Centers (MSCs),
Base Station Controller (BSC), Serving GPRS Support Node (SGSN), Packet
Data Serving Node (PDSN), and so on.We also address the connectivity and
transport requirements between the various network elements.
In general, the design of the core network involves striking a balance
between three requirements—meeting or exceeding the capacity needed to
handle the projected demand; minimizing the capital and operational cost of
the network; and ensuring high network reliability/availability. In short, we
can refer to these three issues as cost, capacity, and quality. Of course, meeting
one or more of the requirements often means making sacrifices elsewhere
such that it is impossible to divorce one network design consideration
from any of the others. For example, a lower cost might well mean a lower
network capacity or a lower network quality. Thus, we will never get a network
that is remarkably cheap to implement and operate while still offering
high capacity and high quality. Instead, we must aim to establish some
“happy medium” where we satisfy at least the most important criteria.