Z. Goldfeld
In Proceedings of the 2016 IEEE Information Theory Workshop (ITW-2016), Cambridge, UK, September 2016
The two-user multiple-input multiple-output(MIMO) Gaussian broadcast channel (BC) with common,private and confidential messages is considered. The transmittersends a common message to both users, a confidential messageto User 1 and a private (non-confidential) message to User2. The secrecy-capacity region is characterized by showingthat certain inner and outer bounds coincide and that theboundary points are achieved by Gaussian inputs. The proofrelies on factorization of upper concave envelopes and a variantof dirty-paper coding (DPC). The entire region is exhaustedby using DPC to cancel out the signal of the non-confidentialmessage at Receiver 1, making DPC against the signal of theconfidential message unnecessary. The secrecy-capacity resultsare visualized using a numerical example.