OSPG-MAC: An OFDMA-Based Subcarrier Pregrouping MAC Protocol for Underwater Acoustic Wireless Sensor Networks

Figure 2

The process of data transmission in the OFDMA-based subcarrier pregrouping MAC (OSPG-MAC) protocol. (a) Sink node sends data to nodes 1, 2, and 3 concurrently. (b) Sink node receives data from nodes 1, 2, and 3 concurrently.

(a)

(b)