The 802.11a and 802.11b physical layers make use of data scrambling (see Appendix 12B). For 802.11, the scrambling equation is P(X) = 1 + X4 + X7 In this case the shift register consists of seven elements, used in the same manner as the five-element register in Figure 12.17. For the 802.11 scrambler and descrambler,

a. Show the expression with exclusive-or operators that corresponds to the polynomial definition.

b. Draw a figure similar to Figure 12.17.