Design and Performance Evaluation of a Distributed OFDMA-Based MAC Protocol for MANETs

Figure 5

An LET4 takes place because local information cannot reflect the network state completely.

(a) At time 𝑡, multiple RTS frames are sent simultaneously. The RTS frames sent by 𝐸 and 𝐶 collide at 𝐵

(b) At time 𝑡+1, multiple CTS frames are sent to confirm reservation

(c) At time 𝑡+2, the data transmission from 𝐴 to 𝐵 fails because it collides with the data transmission from 𝐶 to 𝐷