Compound Gaussian multiple access channels with noisy feedback
Ashutosh Sabharwal, Debashis Dash, Suhas N. Diggavi · 2008
In this paper, we study the role of noisy feedback in compound Gaussian multiple access channels, where both the set of active users and their respective channels are unknown a priori. The system is modeled as a special form of two-way network, where transmitters and receivers can interact with each other to improve the overall communication efficiency, but the information flow is not bi-directional. We first characterize the compound channel capacity when there is no feedback in the system, which turns out to be simply an intersection of several capacity regions. Next, we analyze a polling, channel estimation and feedback protocol, which achieves a rate region to within log(K) bits/use of a K-user system with perfect feedback.