Channel Element (CE) Dimensioning

The Channel Element (CE) dimensioning will obviously be based on the
requirements for both voice- and data-services needs. The total number of
channel elements required will be the summation of both the fundamental
and supplemental channel elements defined for voice and data services.
The new channel element that is being offered by all the major vendors
is compatible with the existing IS-95 system and can be directly substituted
for an existing channel element. However, as discussed later, the full
replacement of all CEs is not practical; based on the deployment options,
used IS-95 legacy systems should be left in place.
For simplification, a channel element (CE) is required for each
■ Voice cell
■ Leg of the soft hand off
■ overhead channel
■ Data call
The dimension of the channel elements is done in increments of 32 or 64
for CDMA2000-1X-capable CEs. Because CEs typically come in 32/64 cards,
it leads to the issue that if 20 CEs are required, a 32-CE card is acquired.
Although in the same sense if 33 CEs are needed, a choice needs to be made
to either under equip or obtain another CE card to bring the count to 64
when only 33 are needed:
■ 32 CE for 13 to 17 percent of cdma-1X full capacity
■ 64 CE for 29 to 44 percent of cdma-1X full capacity
The CDMA2000-1X full capacity is derived based on a fixed environment
and availability of 128 Walsh codes. Obviously the percentages shown previously
depend, of course, on the mix of voice and data traffic within the system
as well as mutual interference.
A rule of thumb to follow is that for sites requiring less than 40 CEs, a
32-element card should be used, but for sites requiring more than 40 CEs,
then the 64-CE card is expected to be used.