1. Show that the sum-rate capacity of the AWGN MAC is achieved by having all users transmit at full power.
2. Derive the optimal power adaptation for a two-user fading MAC that achieves the sum-rate point.
3. Find the sum-rate capacity of a two-user fading MAC where the fading on each user's channel is independent. Assume each user has
(i) a received power of 10 mW and
(ii) an effective noise power of 1 mW with probability .5 or 5 mW with probability