  This paper investigates the capacity region of three-receiver AWGN broadcast
channels where the receivers (i) have private-message requests and (ii) know
the messages requested by some other receivers as side information. We classify
these channels based on their side information into eight groups, and construct
different transmission schemes for the groups. For six groups, we characterize
the capacity region, and show that it improves both the best known inner and
outer bounds. For the remaining two groups, we improve the best known inner
bound by using side information during channel decoding at the receivers.
