Multiuser broadcast erasure channel with feedback - capacity and algorithms

We consider the N-user broadcast erasure channel where feedback from the users is fed back to the transmitter in the form of ACK messages. We provide a generic outer bound to the capacity of this system and propose a coding algorithm that achieves this bound for an arbitrary number of users and symmetric channel conditions, assuming that instantaneous feedback is known to all users. Removing this assumption results in a rate region which differs from the outer bound by a factor O(N2 /L), where L is packet length. For the case of non-symmetric channels, we present modifications of the previous algorithm whose achievable region is identical to the outer bound for N 3, when instant feedback is known to all users, and differs from the bound by O(N2 /L) when each user knows only its own ACK. The proposed algorithms do not require any prior knowledge of channel statistics.

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: Marios Gatzianas, Leonidas Georgiadis, Leandros Tassiulas
• Keywords: CORR 2010, Education, Generic Outer Bound, Outer Bound, Symmetric Channel Conditions