Performance Analysis of Hierarchical Modulation with Higher Spectrum Efficiency for a Higher Date Rate T-DMB System

摘要

In order to improve current transmission capacity of the ancillary data in terrestrial digital multimedia broadcasting (T-DMB) system, the hierarchical modulation is adopted. The hierarchical modulation consists of Higher-priority (HP) data, which is the same as in the legacy T-DMB, and Low-priority (LP) data, which carriers the additional data for the upgrade system, while the backward compatibility is guaranteed. Both QPSK modulation and 4ASK modulation are good candidates for LP data modulation. So in this paper we adopt coherent detection with comb-type pilot arrangement, the Least Squares (LS) estimate of pilot signals and the piecewise-linear interpolation channel estimation. Simulation results show that LP-QPSK provides a better choice than LP-4ASK for achieving a higher data rate in the Advance T-DMB (AT-DMB).