5000-
S4000-
$3000
S2000-
1000-
y (dB)
Figure 4-3: The optimal packet length (PL) vs. SNR (y ), h=128.
0, 10 1,1 t 2 ,2 k-1,k-1
Figure 4-4: Packet-Length-Based finite-state Markov channel model.
According to [98], for a given crossover probability p, the optimal packet length,
which is a function of p, can be written as
-h ln(1 p)- -4 n1-p+h22
PL =(4.3)
2 In(1 p)
where h is the number of overhead bits per packet. Fig. 4-3 shows the relationship between
the received SNR and the optimal packet length. For a given state Sk, the average optimal
packet length PLk for this state can be derived by using (4.1), (4.2), (4.3) to be
Based on the above analysis we present our packet-length-based FSMC model in Fig.
4-4. We represent each state as the average packet length PLk, which is the packet size for
a transmission in state k. The transition probabilities between different states are denoted