gner. We also can create call state diagrams for each aspect of cellular technology: for call maintenance, for power control for handoffs, and so forth. Soft handoff improves CDMA call performance, at some cost of capacity, and it increases the radio state space con- siderably. Not only are soft and softer handoffs (described in Sec. 8.7) themselves more involved than the older hard handoffs, but soft-handoff systems also still have to sup- port hard handoffs between CDMA carriers, between CDMA and analog, when the pi- lots are not compatible for soft handoff (disjoint active sets), or when there are not enough radio resources (frame offsets) to support soft handoff. There is one piece of good news in wireless call state analysis. The call-processing states and the radio states are almost completely independent. From the call process- ing point of view, establishing the radio link is part of a single step, and the call-main- tenance tasks of power control and handoff occur completely behind the scenes. And from the radio link point of view, the call processing is almost as invisible. Custom call- ing features require an occasional SEND key, but otherwise the radio link does not even know if the call was completed. A completed call and a busy signal are both voiceband signals. There are two exceptions to this rule, and both are relatively benign. The first is that user terminals have restrictions and conditions of service more complex than landline telephones. Landline telephones are active or they are not active, whereas wireless telephones, even fraudulent or in default, can still make emergency calls according to One glare condition observed by one of the authors (Kemp) appears to be the result of a design error in message handling. This is a case where a CDMA cellular telephone is turned on by the subscriber and, as the user is dialing digits, a signal comes in informing the user of new voice mail. The telephone enters a state where the user is unable to make a call out until the subscriber ei- ther checks the