Laboratory performance assessment for DRM+ system in single and dual-antenna transmission scenarios

It has been shown that due to its smaller signal bandwidth (96 KHz), DRM+ signal could suffer from flat fading degradation at low receiver speeds, particularly in urban environments. To alleviate this problem, a simple transmit delay diversity (TDD) has been proposed in the standard. This paper tries to investigate this issue by presenting the performance results of multipath fading characterizations performed in the laboratory for DRM+ system. Both single and dual-antenna transmission scenarios have been considered. By using a sophisticated hardware channel simulator, different radio channel models corresponding to various scenarios and environments (urban, suburban, mountain, SFN, etc) could be tested and compared. For a single antenna scenario, the results show that indeed, at low receiver speeds (5 km/h), the DRM+ receiver was unable to cope with the effect of flat fading in the urban channel model. However, in the same environment, TDD scheme provides 3 dB gain over single antenna transmission if low or moderate correlation level is maintained between the two signal paths. Moreover, it has been found that for a TDD enhanced DRM+ system, a better performance is obtained with the SFN channel model as compared to urban and rural channels when the two signals are highly correlated.