4. Gentle" intercellular transfer

All existing cellular systems use handover procedures based on cutting the link between the cell from which the mobile comes and the mobile itself, while simultaneously establishing a link with a new cell. The result is a slight disconnect perceptible to the ear and, above all, a non-negligible risk of losing the call in progress. The CDMA system uses another automatic handover technique, which we'll call "soft" because it doesn't involve any transmission interruption. The process is illustrated in figure 4 .

When a mobile is about to perform a cell handover, it is followed by at least two cells. The CDMA transcoder compares the quality of the frames received by the two cells, frame by frame. The system is then able to take advantage of instantaneous level changes...