In CDMA (Code Division Multiple Access) systems, the breakdown of the uplink as the number of users approaches the theoretical maximum is primarily due to cochannel interference. As more users are added, the signal-to-noise ratio (SNR) decreases because all users share the same frequency band and spread spectrum codes, leading to increased interference among the signals. When the number of users reaches the theoretical maximum, each user's signal begins to interfere with others, which causes the mobiles to request more power to maintain their connection quality. This increased demand for power can lead to a situation where not all users can be adequately supported. In such scenarios, the mobiles that will have their connections dropped first are typically those with the weakest signal quality or the lowest transmission power. These are usually users who are on the edge of the cell coverage area or those who have poor radio conditions (e.g., due to physical obstructions or distance from the base station). As the system becomes overloaded, the base station may prioritize stronger signals, effectively dropping the weaker users first to manage overall system performance and maintain quality for those with better connections.