In cooperative communication system, different nodes cooperate with each other based on a certain protocol. We propose a new scheme for multiple access communication system in which the two cooperating nodes transmit their own data and their partner's data on orthogonal carriers and thus exploiting full degrees of freedom. With two cooperating nodes, we achieve full diversity of order two and at the same time we maintain the data rate for the two streams from the two sources. We compare our results in terms of error probability and outage probability with non-cooperative and a network-coding cooperative scheme. We also show the increased reliability of cooperative modulation scheme.