G是帧传输时间内系统产生的帧的平均数量 Note The throughput for pure ALOHA is S=GX e-2G The maximum throughput Smax 0.184 when G=(1/2). 纯ALOHA的吞吐量是S=GXe-2G ,当G= (1/2)时，最大吞吐量为Smax=0.184 12.11
12.11 The throughput for pure ALOHA is S = G × e −2G . The maximum throughput Smax = 0.184 when G= (1/2). 纯ALOHA的吞吐量是S = G × e −2G ，当G= (1/2)时，最大吞吐量为Smax = 0.184 。 Note G是帧传输时间内系统产生的帧的平均数量
Figure 12.6 Frames in a slotted ALOHA network 时隙ALOHA网络中的帧 Collision Collision duration duration Station Frame 1.1 Frame 1.2 Time Station 2 Frame 2.1 Frame 2.2 Time Station 3 Frame 3.1 Frame 3.2 Time Station Frame 4.1 Frame 4.2 Time Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 12.12
12.12 Figure 12.6 Frames in a slotted ALOHA network 时隙ALOHA网络中的帧
Figure 12.7 Vulnerable time for slotted ALOHA protocol 时隙ALOHA网络中的帧，其可能的冲突时间是帧长度的1倍。 A collides with C B A ! C 器 t-Tfr t+Tfr Time Vulnerable time=Tfr 12.13
12.13 Figure 12.7 Vulnerable time for slotted ALOHA protocol 时隙ALOHA网络中的帧，其可能的冲突时间是帧长度的1倍
UNIN Note The throughput for slotted ALOHA is S=G×e-G. The maximum throughput Smax 0.368 when G=1. 时隙ALOHA的吞吐量是S=GXe-G,当 G=(1)时，最大吞吐量为Smax=0.368 12.14
12.14 The throughput for slotted ALOHA is S = G × e −G . The maximum throughput Smax = 0.368 when G = 1. 时隙ALOHA的吞吐量是S = G × e −G ，当 G= (1)时，最大吞吐量为Smax = 0.368 。 Note
Figure 12.8 Space/time model of the collision in CSMA CSMA中冲突的时空模型 B starts C starts at time t at time t2 A B D ti - t2 Area where A's signal exists Area where both signals exist Area where B's signal exists Time Time 12.15
12.15 Figure 12.8 Space/time model of the collision in CSMA CSMA中冲突的时空模型