Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 24

Since the ranging procedure in a PON has limited accuracy, a guard time is placed between consecutive bursts from the ONTs to avoid collisions of the independent packets, as Fig. 7.18 illustrates. Verify that a 25.6-ns guard time consumes 16 bits at 622 Mb/s, 32 bits at 1244 Mb/s, and 64 bits at 2.488 Gb/s.