Proceedings of the IEEK Conference (대한전자공학회:학술대회논문집)
- 2001.09a
- /
- Pages.249-252
- /
- 2001
A Comparative Study of Branch Metric Calculator in QAM-TCM Decoder
QAM-TCM 복호기의 가지척도계산방식 비교 연구
Abstract
TCM(Trellis Coded Modulation) has soft decision scheme so that BM(Branch Metric) calculates the ED(Euclidean Distance) between the received signal and each code words in signal space. For computing the ED, square and square root computations increase the hardware complexity. Some simplified method is known for convolutional codes with QPSK(Quadrature Phase Shift Keying), PSK(Phase Shift Keying) modulation. But it is not acceptable for QAM (Quadrature Amplitude Modulation)-TCM scheme. In this paper, we suggest that two modified BM computation methods, which is applicable for QAM-TCM. By comparative study, we also assessed two proposed method in the case of hardware complexity and BER (Bit Error Rate) performance.
Keywords