DOA Estimation using MUSIC Algorithm and Biological Inspired Optimization Technique for Array Geometrics

DOA Estimation using MUSIC Algorithm and Biological Inspired Optimization Technique for Array Geometrics

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Suprith Kumar K S1, S. Akhila 2,

1, 2 Department of ECE, BMS College of Engineering, Bangalore, India

Abstract– Navigation systems and location technologies are seeing rapid progress in many fields such as military sonar, satellite communication and radar systems. The received signal is very weak due to various environmental conditions that change dynamically. So, in order to increase the strength of the received signal and to improvise the radiation pattern, the signals have to be processed using adaptive Array Signal Processing (ASP) technique. An adaptive smart antenna system consists of a set of antenna elements and a signal processor that adapt its radiation pattern to focus the reception of array signals in the required direction and reject the signals from interfering direction. Techniques used to produce such radiation pattern by calculating the excitation weights is called Adaptive Beam Forming (ABF) technique. The performance of this technique largely depends on Direction of Arrival (DOA) of the signal and Signal to Noise Ratio (SNR). This calls for development of a robust ABF technique. In this work, Particle Swarm Optimization (PSO) technique is used to achieve ABF and suppression of side lobes.

Key words– Adaptive Beam Forming (ABF), Array Factor (AF), Array Signal Processing (ASP), Direction of Arrival (DOA), Multiple Signal Classification (MUSIC), Particle Swarm Optimization (PSO).

field of research. Whereas Beam forming is a technology used in arrays to get directional radiation pattern at specified angles. The main lobe [8] is the lobe with maximum magnitude. This means the array can transmit more energy in

the direction of main lobe when it is used as a transmitter or on the other hand, the signal from that direction will be received better if the array works as a receiver. Often the radiation pattern of the array needs to be adjusted to satisfy various requirements. The radiation pattern is determined by several parameters such as nature of elements in the array, geometry of the array, the excitation coefficients of each element etc. An array consisting of multiple elements is used for improving the radiation pattern without changing the characteristics of individual elements. Compared to individual elements, an array can achieve higher directivity, higher gain and a lower SLL. The most common geometry for arrays are linear, rectangular and circular. This paper is organized as follows- Section 2 gives the related work, section 3 gives the method used for adaptive beamforming using the PSO technique, Section 4 gives the simulated results followed by the analysis. The paper concludes with section V.

I. INTRODUCTION

End to end communication requires highly directive beam of radiation [1].This is achieved by placing several antennas in the form of an array. Research on DOA estimation [2] is done as a part of array processing. Over few decades, wireless communication has gained the momentum due to its flexibility and convenience. For advanced services, a high-speed data rate is the need of the hour which requires higher frequency bands.But at higher frequencies cross interference and multipath fading becomes a major problem. Smart antenna systems can be used to overcome such problems. These smart antennas [7] have signal processing capability which are used to identify direction of arrival of the signal. Once the direction is identified, beam forming vectors are calculated which helps in tracking the target. There are several algorithms available to estimate the DOA of the signal such as Multiple Signal Classification (MUSIC), Estimation of Signal Parameters via Rotational Invariance Techniques (ESPRIT) algorithm. These techniques are useful in finding the DOA from the peaks of the spectrum. DOA estimation is still an evolving and active

II. RELATED WORK

2.1 DOA Estimation using MUSIC Algorithm2.2 Improved MUSIC Algorithm4.1 The basic direction of arrival estimation:4.2 DOA estimation with respect to array elemental spacing:4.3 DOA estimation with respect to number of elements:4.4 DOA estimation with respect to number of snapshots:4.5 DOA estimation with respect to SNR:4.6 Detection of coherent signals using improved MUSIC Algorithm:4.7 Adaptive Beam forming using PSO:

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