Alice and Bob are experimenting with CSMA using a W₂Walsh table (see Figure 12.29). Alice uses the code [+1, +1] and Bob uses the code [+1, ˆ’1]. Assume that they simultaneously send a hexadecimal digit to each other. Alice sends (6)₁₆and Bob sends (B)₁₆. Show how they can detect what the other person has sent.  

Figure 12.29

+1 +1 +1 +1 +1 W4 : -1 +1 -1 +1 +1 W2 WN Wi = +1] W2N = +1 WN +1 -1 -1 -1 +1 +1 -1 WN -1 +1 WN b. Generation of W2 and W4 a. Two basic rules