An Experimental Study of the DOA Estimation Using the Fast DOA Algorithm in Urban Area
Ami Kanazawa, Y. Nakagawa, T. Fukagawa, Hiroyuki Tsuji, Hiroyo Ogawa · 2000
We report on our experimental estimation of the direction of arrival of a signal by using the adaptive array antenna equipment in an urban area. The result demonstrates the DOA estimation using a fast DOA algorithm and improved BER performance by using this estimated DOA. In a macro- or micro-cell system with a radius of 500-2000 m, a one to two GHz frequency is now used, but it has become a crowded. The number of personal digital cellular system (PDC) and personal handyphone system (PHS) subscribers in Japan has reached 60 million. Moreover, the available services have grown from voice to data to picture. This means that techniques that effectively reuse frequency resources while improving a quality of signal (QoS) are required. The use of the adaptive array antennas in mobile communication systems is one technique to improve channel capacity or QoS by reducing co-channel interference and multipath fading. An array antenna is installed at a base station (BS), the desired signals can be received while undesired ones can be suppressed. This results in an improvement of the quality of the up-link signal. Moreover, by controlling the antenna gain at the transmission point, the BS can avoid transmitting in undesired directions. As a result, the quality of the down-link signal also improves because interference signals from other BSs are suppressed at the users’ position. At the viewpoint of the frequency reuse problem, the improvement of CIR makes it possible to reduce the channel reuse distance keeping the required QoS. To achieve the type of control described above, being able to estimate the direction of arrival (DOA) of a signal and to determine the antenna weights are the important problems to surmount. We need to especially clarify the performance of DOA estimation when the target user is moving at high speed. In this paper, we report on the performance of our DOA estimation of a user moving at 40 km/h in an urban area with a particular condition. In Section 2, we describe the system concept of using an array antenna at a BS. In Section 3, we explain our experimental equipment and report the results of our experiments in an urban line-ofsight (LOS) environment. We summarize our report in Section 4.