Serial concatenation scheme with a space-time trellis code as the outer code and recursive convolutional codes as the inner code are compared. A new encoding/decoding structure characterized by the inner encoding by a single recursive convolutional code and the combined decoding of simultaneous symbols from multiple antennas is proposed, which gives a large performance gain over the original multiple inner encoding/separate decoding scheme and enables a decoding algorithm much simpler than the multiple inner encoding/joint decoding scheme. Simulation results for a communication system with two transmit and a single receive antennas in quasi-static, flat Rayleigh fading channels are presented.