Overlapped Time Division Multiplexing System Using Turbo Product Code

A new coded Overlapped Time Division Multiplexing (OVTDM) system, called TPC-OVTDM, is presented in this paper. The new scheme uses Turbo Product Code (TPC) as Forward Error Correcting (FEC) code in OVTDM system. Through analyzing the uncoded OVTDM signal structure and its Bit Error Rate (BER) in low-to-moderate Signal to Noise Ratio (SNR), utilizing an FEC with fast iterative convergence behavior is a good choice. TPC satisfies the requirement and is easy to be implemented in hardware. Simulation results also show that with the increase of spectral efficiency, the TPC-OVTDM scheme can achieve greater coding gain than TPC plus Quadrature Amplitude Modulation (TPC-QAM) under the condition of same spectral efficiency. In addition, the new scheme proposed in this paper makes system's cardinality of signal constellation increase polynomially with spectral efficiency, rather than that of QAM signal which grows exponentially.