Fixed Network Design Requirements

The introduction of packet data services of course not only requires the
focus on the radio environment for a CDMA2000 system, but also on all the
supporting elements that comprise the wireless system. Therefore the following
are the major elements that need to be factored into the design of a
CDMA2000 system:
■ Mobile Switching Center (MSC)
■ Baser Station Controller (BSC)
■ Base Transceiver Station (BTS)
■ Packet Data Service Node (PDSN)
In reviewing the previous list, several nodes or elements directly associated
with radio elements are listed. The reason the BSC and BTS are listed
in the fixed network design requirements lies in the simple concept that
connectivity needs to be established between the BTS and the BSC,
whether it is via landline services or via a microwave link. The BSCs are
listed not only because it routes packet and voice traffic, which requires a
certain link dimensioning, but also the BSCs can be local or remote to the
MSC depending on the ultimate network configuration deployed.
The fixed network design includes not only element dimensioning
but also dimensioning the links that connect the various nodes or elements
in order to establish a wireless system. Some of the connectivity
requirements involve the following elements listed next. It is important
to note that all elements require some level of connectivity whether it is
from the Digital Cross Connect (DXX), also referred to as DACS, to the
MSC, or between the voice mail platform and the switch. However, the
list that follows involves elements that usually require an external
group to interface with while the internal nodes are more controllable.
■ Link between BTS and BSC (usually a leased line)
■ Link between BSC and MSC (if remote)
■ BTS/BSC concentration method
■ Connectivity of the PDSN
■ Router (for internal)
■ Router (for external)
■ AAA
■ HA
■ Sentence Creation Server (SCS) and other servers
■ Interconnection to the public and/or private data networks
Note as a general practice the routers used for the packet data network
for 1XRTT applications should not be utilized for other functions, such as
company LAN work.