Spatial diversity analysis for digital TV systems

Spatial diversity for digital TV systems has been studied using the results of a measurement campaign of the radio channel complex frequency response for two different situations: an outdoor-indoor channel and an indoor-indoo r channel. It is shown that the actual improvement of spatial diversity is not only the mean level increase, but the reduction of both the level cross ing rate (LCR) and the average fade duration (AFD). The mean level gain is in the range [1.2-3] dB for the indoor-indoor channel and within [1.4-2.9] dB for the outdoor-indoor channel and the LCR/AFD improvement is between 9. 5 and 15 dB for both environments. To explain the behavior of the diversity system, high resolution angle of a rrival and delay information was obtained. It is concluded that it is the i nterference of the direct propagation path with the main reflections that c auses the received field to follow a standing wave pattern and shapes the s patial diversity gain behavior.