In wireless networks, coded cooperation is a way of realizing uplink transmit diversity at the mobile user with single antenna. In this work, in order to increase the power and bandwidth efficiency, a multilevel coded cooperative system using orthogonal signalling is proposed. Orthogonal signalling not only enables transmission of both users data in single channel symbol but also provides independent detection at the receiver. We investigate the performance of the system by derivation of pairwise and bit error probabilities together with Monte-Carlo simulations.