The Performance of Serial, Matched-Filter Packet Acquisition Using Transmit and Receive Antenna Diversity

The performance of serial, matched-filter acquisition is evaluated for asynchronous packet radio communications using transmit or receive antenna diversity. Transmit diversity is achieved using dual antenna transmissions of orthogonal preamble sequences and receive diversity is achieved using dual antenna reception of a single preamble sequence. Sequential test statistics are formed using non-coherent combining of the outputs from the orthogonal preamble matched-filters if transmitter diversity is used; the test statistics are formed using non coherent combining of the outputs from the preamble matched-filter in each receiver chain if receiver diversity is used. Threshold-based acquisition of the test statistics using both fixed and adaptive acquisition thresholds is considered. The effect of the intermediate-frequency filter and the automatic gain control subsystem on the acquisition performance is accounted for. The performance is evaluated in additive white Gaussian noise channels with constant and slowly varying gains (i.e., a slow-fading channel). The effect of fixed and adaptive acquisition thresholds on the link outage probability is compared for each dual antenna diversity acquisition system. The acquisition performance using transmit or receive antenna diversity is compared with the performance of a system lacking antenna diversity, for both fixed and adaptive threshold acquisition.