(CDMA and FDMA) Suppose that there are 100 users but on average only 10 of them use the system at any one time. Each has average power S when active, and the background noise has power spectral density of N0/2.
(a) Suppose that in FDMA the available bandwidth is divided into 10 equal segments and 10 people are assigned to each of them. Any active user can expect that one other user will be active on the same sub-band. Write an expression for the capacity enjoyed by a user.
(b) In CDMA an active user can expect to see pseudorandom noise from 10 other users. Write an expression for the capacity enjoyed by a user.
(c) At low signal-to-noise levels, which system gives users the greater capacity?
(d) ∗Does one of these systems always have more capacity than the other?