On the Sum-Capacity of Degraded Gaussian Multiaccess Relay Channels

The sum-capacity is studied for a K-user physically degraded Gaussian multiaccess relay channel (MARC). Decodeand-forward (DF) is shown to achieve the sum-capacity and capacity region for a sub-class of degraded Gaussian MARCs in which the multiaccess link from the sources to the relay is the bottle-neck link. For the remaining sub-class, DF is shown to achieve the K-user sum-capacity when the sources are symmetric, i.e., they transmit with the same transmit power. The optimality of DF is conjectured for the case of asymmetric sources.

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Lalitha Sankar, Narayan B. Mandayam, H. Vincent Poor
• Keywords: Capacity Region, CORR 2008, Education, Gaussian Multiaccess, Relay