ls to add to the sector handoff neighbor lists. We are loathe to remove a handoff neighbor candidate that looks good on the cookie-cutter map, but we are certainly anxious to include a candidate suggested by a planning tool, even if is not visible on the map. It is important to maintain the neighbor lists as new base stations are added to the CDMA wireless telephone system. It is also important to manage the add and drop pa- rameters for soft handoffs. 42.8 Reliability Issues for Growth Cells When we built the original cell layout, we decided on a level of reliability for our wire- less telephone system. This reliability requirement was the input to the decision of what kind of equipment and how much redundancy to put in each base station we were building. Now we are adding base stations to create growth cells to serve more traffic. These new base stations are required to serve the increasing demand for wireless tele- phone service while keeping the quality of service (QoS) high. If a growth cell base station fails, then the system will experience a decrease in its QoS below the level required. If this were not the case, then we would not have added the new cell. However, the system worked without the growth cell when there was less traffic. We may decide that serving less traffic is acceptable for the relatively rare and brief periods that a growth-cell base station is out of service. The loss of the growth cell would bring us back to the system as it was before the growth cell was added and the system had full coverage of the service area. The result of this reasoning is that we should consider the cost savings of adding growth cells without extra equipment for redundancy. Over time, the subscriber demand may be great enough that we will change our minds and decide that these cells are too important to be left without redundant equipment. However, the initial installation of a growth cell may be a lot less expensive if we can live without duplicate systems. Downloaded from Digital Engineering Library @ McGraw-H