An Improved Signal Superposition Modulation for Cooperative Transmission
In this paper, a novel cooperative transmission strategy based on the orthogonal superposition modulation (OSM) combined with constellation rearrangement (CR) is proposed. This scheme can be an enhancement to the decode-and-forward cooperation, where two user nodes transmit the superposition of both users signals by turns. Furthermore, CR is introduced into the superposition process to improve the cooperation performance and efficiency. The corresponding symbol error rate (SER) in the Rayleigh fading channel is analyzed and a tight conditional SER upper bound in a closed form is derived. Simulation results confirm the effectiveness of OSM-CR scheme, and show that it significantly outperforms the conventional SM and OSM methods without increasing complexity.
orthogonal superposition modulation (osm) constellation rearrangement (cr) symbol error rate (ser) cooperative diversity