In CDMA cellular phone systems, a smooth transition from one cell to another. Unlike analog FDMA and digital TDMA systems, which use different frequencies in adjacent cells, CDMA uses the same frequencies but codes each conversation differently. As you move between cells, a CDMA phone picks up the same coded signal on the same frequency from both cells. When the original cell stops transmitting, the phone is already receiving the signal from the new cell causing a smooth transition with less chance of a dropped signal. See
CDMA.