  In this paper, we study the problem of best transmission link selection in a
decode-and-forward (DF) cooperative system from capacity point of view. The
transmission link can be a cooperative (via a relay) or direct link between the
source and destination nodes. In a two-hop DF system with multiple relays and a
direct link in between the source and destination, the transmission link
selection can be performed based on full or partial channel state information
(CSI) of all links involved in cooperation. We derive analytical ergodic
capacity of full and partial CSI based path selection schemes in the DF
cooperative system. Further, the full and partial CSI based link selection
schemes are compared with help of these expressions.
