riorates. Depending on the speech coder, the subscriber may hear lower quality or short periods of dropouts, but either way, the performance drop is audible. Customer perception of low sound quality has a lot to do with the time intervals in- volved. A listener facing 30 seconds of steady bad sound in a 10-minute call is going to notice the loss of performance after a few refrains of "Could you say that again?" The same listener experiencing ten 3-second intervals of bad sound may miss a word here and there but can fill in the details from context. And 100 dropouts of 300 ms during the same 10-minute call will lose syllables here and there, and the user may not notice any problem at all. All three of these examples are 5 percent signal outage, but the lis- tener's perception of the outage is quite different. Brief periods of CDMA carrier overload can come from changing radio conditions. When subscribers change their own radio paths by walking into buildings or driving into tunnels, they expect their mobile calls to take a few seconds to adapt, about the same amount of time it takes their eyes to adapt to the changing light. However, in CDMA, every other user terminal on the same cell or on a nearby cell is a significant part of the radio environment of a given user's call and contributes to the quality of the call. When somebody else walks out of a building, however, that user terminal has a much higher path gain and will create excessive interference on the CDMA carrier un- til its power is reduced. There also will be changes in radio conditions as vehicular traf- fic blocks the radio path between user terminals and base stations. These environ- mental changes can cause brief periods of high CDMA interference and low speech quality. Another cause of brief periods of high interference are bursts of activity from high- speed data terminals. A wireless Web surfer downloads an image in the forward direc- tion or a multimedia message service (MMS) subscriber uploads a snapshot in the re- verse direction, and there is