in diag- nosing the wireless system problems that are causing customer complaints. When a call fails in a radio system, it could be a lack of signal strength or it could be a lack of capacity. The CDMA air interface blurs the distinction between coverage and capacity. The CDMA carrier can lose a call because some other call was made, perhaps on a different cell. The CDMA capacity resource is a link budget, and more of that capacity budget is consumed as a user terminal moves away from the base station during a call. Lower radio-signal path-gain calls consume transmit power, and the carrier runs out of capacity when that transmit power runs out. This is true in both the forward and re- verse directions. We expect to see user complaints when the CDMA carrier is close to its full capacity. As it overloads, calls are blocked, voice calls are degraded, and calls are dropped. Es- pecially in a small-cell scenario, a carrier operating at very low power can suddenly find itself in an overloaded state with less than enough bits and Eb/No to go around. Data users may have a different perception of degraded performance from voice callers. Data services can become slow or can develop errors. 40.2 Ineffective-Attempt Complaints Ineffective attempts are calls attempted by subscribers that do not get started. Typi- cally, the reason a call does not happen after a subscriber presses the SEND button or after somebody calls the user terminal is a lack of room on the air interface for another call. We should keep in mind, however, that call-attempt failures can be caused by equipment failures or a lack of resources elsewhere in the system. Especially in a small-cell, high-density area, air-interface blocking is usually due to the fact that there are already so many bits that there is not room for another call. We are climbing up the steep part of the curves of Figs. 28.1 or 28.2, and it does not mat- ter how much transmit power we find in the forward or reverse direction. This is the case most like conventional reuse (FDMA or TDMA)