Digital Beam Forming Using Software Defined Radio Based Adaptive Algorithm

P. Ragasudha, B. R. Vikram, K. Sridhar

This paper presents the development of an Adaptive Digital Beam Forming (ADBF) application on Software Defined Radio Platform using Open Source GNU Radio software. Adaptive beam formers for sensor arrays are widely used in RADAR, SONAR and communications applications. This is to increase the directivity of the sensor system to the target, while suppressing the interfering signals having a direction of arrival different from that of a desired signal. Array beam forming techniques can yield multiple beams that are simultaneously available. The beams can be made to have controlled beam width or high gain and low side lobe levels.Beam-forming techniques dynamically adjust the array pattern to optimize some characteristic of the received signal. Antenna arrays using beam-forming techniques can reject interfering signals having a direction of arrival different from that of desired signal. The principal reason of interest is their ability to automatically steer nulls into undesired sources of interferences, thereby reducing output noise and enhancing the detection of desired signal. Beam forming and beam scanning are generally accomplished by phasing the feed to each element of an array so that signals received from all the elements will be in phase in particular direction. Digital beam forming is thus a powerful technique for boosting the antenna performance. The work reported in this paper is purely a software based approach where all the waveform-specific processing is implemented on host CPU. The results supporting the presented work are furnished in this paper.