Fig. 1
From: Performance analysis of feedback-free collision resolution NDMA protocol
Slotted random access assisted by retransmission diversity and MPR for FF-NDMA with R = 3. The frame is composed of contention periods (CPs), each containing R consecutive time slots. Devices access the shared channel whenever they have a packet to transmit at the CP start. As an example, two and four devices transmit in the first and second CPs, respectively