In this paper, different power allocation schemes between the source and the cooperating relay nodes are analyzed and numerically evaluated for a two-hop decode-and-forward OFCDM based relay network. A cooperative power allocation ratio ?? (=source power/total power) is defined and BER performance is evaluated for different values of ?? in the relay network. It is shown that there exists an optimal power allocation ratio for different operating environment such as source-to-relay channel gains and time-frequency spreading factors. It is reported that (a) When all three channels (source-to-relay, source-to-destination and relay-to-destination) have equal gains, power ratio is found to be ?? ?? 0.8 (i.e., 80% and 20% of the total power is distributed among source and relay node respectively). The BER performance degrades at a faster rate when ?? increases above the optimal value than the decrement at higher Eb/N??. (b) For a network with stronger source-to-relay link, the optimal ?? remains invariant at higher Eb/N?? for equal channel gain case; however, the optimal power ratio moves toward lower value of ?? at lower Eb/N??. (c) The optimal ?? remains almost the same with different time-frequency spreading factors.