Low complexity hybrid analog/digital phased array for ad-hoc networks

This paper investigates a hybrid analog/digital beam former (ADBF). Traditional analog beam formers (ABF) steer a single beam using a single transceiver, power splitter/combiner, and electronically controlled analog phase shifters. In contrast modern digital beam formed arrays (DBF) or `smart antennas´ use separate transceiver chains, A/D and D/A converters, and DSPs. This enables direct digital control of array weights to optimize criteria such as mean square error (MSE) or signal-to-interference ratio (SIR) in real time. DBF technologies are effective but are not suitable for every application due to their relative high cost and complexity. The technique proposed here is similar to ADBF approaches using a single transceiver and analog phase shifters, but phase shifters are digitally controlled to provide flexible multiple nulls and beams defined in real time.