Pilot Channel Allocation

The location within the AMPS spectrum that the primary and secondary
IS-95 pilot channels are supposed to operate at is shown in Figure 3-22,
which is further clarified in Table 3-5, the CDMA channel designation channel
table.

The CDMA channel assignment for cellular is defined as requiring the
primary or secondary CDMA channel defined in the table to be utilized. The
rational behind this issue lies in the initialization algorithm that is used for
CDMA. Simply put, if the subscriber unit, dual mode, does not find a pilot
channel on either the primary or secondary channel, then it reverts to an
analog mode.

Figure 3-23 is a brief illustration of where a second CDMA carrier could
be placed for, say, a B band operator. Specifically, the fact that a preferred
channel is used enables the deployment of a second CDMA carrier that is
more congenial for the operator. In this case, the second channel is planted
next to the primary preferred channel and the guard band is now shifted up
in frequency.

PCS, on the other hand, has a different set of preferred channels that are
recommended. The initialization algorithm is simply when the subscriber
powers up, it will search in its preferred block, A through F, for a pilot channel using the preferred channel set located in Figure 3-24. The preferred
channels are designated by the PCS operator that the subscriber has contracted
mobile service from. The pilot channels can, like cellular, also exist
in any of the valid ranges listed in the table.

Additionally, the comments listed as conditionally valid (cv), are based
on the premise that the operator has control of the adjacent block of frequencies.
The comments could also be based on the fact that both of the adjacent blocks like C and F utilize CDMA technology, therefore eliminating
the need for a guard band on each side of the allotted spectrum. 97