国家重点实验室 Example:BEC o Assume that W is a BEC with the erasure probability &=0.5 Because of the recursive construction of the BEC channels,the parameters C(W)can be computed through the recursion C(w2-)=(C(w9)j C(W2)=2(C(w9)-(CW9)Example: BEC Assume that W is a BEC with the erasure probability Because of the recursive construction of the BEC channels, the parameters can be computed through the recursion 22 ε = 0.5 ( ) ( ) i C WN ( ) () ( ) ( ) () ( ) ( ) ( ) 2 2 1 / 2 2 2 /2 /2 ( ) () ( )2 ( ) ( ) i i N N i ii N NN CW CW CW CW CW − = = −