Cell breathing, also known as cell respiration, refers to the phenomenon in CDMA systems where a base station’s coverage area shrinks as more subscribers connect. Unlike traditional systems where each subscriber gets the full transmission power, CDMA systems divide the base station’s output power among all active subscribers. For example, with 20 watts available, the network can allocate 10 watts to two subscribers or 2 watts to ten subscribers. The available power for an individual subscriber decreases as more subscribers connect, resulting in a reduced coverage range. This concept applies to systems like UMTS and CDMA2000.