We investigate joint cooperation diversity and symbol mapping diversity strategies for cooperative space-time coding system that employs nonbinary linear modulations. Substantial symbol error rate gains results from different symbol mappings for each packet transmission (symbol mapping diversity) and independent delivering paths to the final destination (cooperation diversity), which can combat the effects of fading induced by multipath propagation and provide substantial symbol error rate gains with only a small increase in receiver complexity. The BER performance of four types of cooperative communication systems are analyzed and compared in this paper and simulation results show that joint diversity scheme has the best BER performance.