A study on detection of receiving signal status change with array antenna

In beam forming with array antenna so-called adaptive array antenna, typically initial acquisition including reference signal detection and synchronization is required as preprocessing. Performance of the initial acquisition by correlator, such as matched filter, degrade the performance due to carrier frequency offset. A countermeasure for carrier frequency offset usually requires significant computational cost, in addition it requires to be performed symbol-by-symbol. In fact, the initial acquisition problem is approximately equivalent to detecting status change of received signal. The status is indicated by the received signal power and direction of arrivals, the status change may be caused by new signal arrival. In our new approach, the matched filter with countermeasure for carrier frequency offset is used only if the status changed is detected and in this paper, we only focus on the status change detector. Energy detector (ED) also has a capability to detect the status change, in addition the detection performance is not affected by carrier offset and the complexity is very low. However, co-channel interference makes the ED difficult. In our proposed method, the test statistic is designed based on covariance matrix which include not only energy information but also direction arrival information, therefore it can achieve better detection performance than the ED. Computer simulation results will show validities and benefits of the proposed method.