A new random access system, like ALOHA, is presented in this paper, where each mobile node will either be in a transmitting mode, in a receiving mode or in an idle mode. Results show that the traffic load is independent of the number of nodes, and can be controlled by controlling the transmitting probability, receiving probability and idle mode probability of each mobile node. Certainly, the presented access scheme is suitable for ad hoc and sensor networks, where mobile nodes are transmitting and receiving signals among each other without any central entity, and the number of mobile nodes within operating range cannot be controlled. The system is studied in terms of node transmitting probability, node receiving probability and node idle probability.