Diversity Transmission for Correlation-Based Slot Synchronization with Noncoherent Combining

We analyze MIMO diversity transmission of synchronization signals in a slot synchronization scenario typical in modern wireless communication systems. Assuming a threshold-based correlation detector with noncoherent combining of diversity branches at the receiver, we derive general analytical expressions for probabilities of false alarm, detection and missed detection for a frequency-selective MIMO channel, and study the effects of diversity and channel correlation to these quantities. We apply the theoretical analysis for the usual SIMO case, cyclic delay diversity, time-switched transmit diversity, orthogonal transmit diversity and the precoding vector/matrix switching techniques. We verify the theoretical analysis through simulations in a practical 3GPP LTE context. Finally, we evaluate performance of the diversity schemes in different scenarios using the derived theoretical expressions.