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Among the mobile ad hoc networks appealing characteristics there are network reconfigurability and flexibility. In this context a smart antenna capable of self-configuring multiple high-directivity beams provides a major advantage in terms of power saving, increased range, and spatial reuse of channels. In this paper a smart antenna made of a cylin...
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... Then, they propose an efficient CH scheme that can be combined within the SH schemes. Authors in [14] studied a smart antenna made of a cylindrical array of patches suitable for MANETs. In this study, they evaluated a smart antenna capability of self-configuring multiple high-directivity beams. ...
... Recently, there has been increased interest in directional communication, which provides significant improvements by enabling the spatial reuse, extending coverage, mitigating interference, and thereby increasing the network capacity [1][2][3]. At the same time, the recent advances in antenna technology, along with the shift toward higher frequencies, have made the design and use of multi-beam directional antennas (MBA) more feasible [2][3][4][5][6][7][8][9][10][11][12][13][14]. Since the use of directional antennas divides the space around them in different beams, a multi-beam antenna with m beams can allow multiple (up to m) concurrent packet transmissions (CPT) or receptions (CPR) by a node using the same spatially overlapped channel, thus improving the throughput by up to m times as compared to the single beam directional antenna [1][2][3][4]. ...
Recent advances in antenna technology have made the design of multi-beam antennas (MBA) feasible. Compared to an omni-directional or a single beam directional antenna, an MBA equipped node can achieve a throughput of up to m times, by simultaneously communicating on its m non-interfering beams. As a result, a few multi-beam directional medium access control (MAC) schemes have been proposed in the literature recently, which are implemented mostly on the in-house simulation setups in Matlab or C/C++. These implementations make many assumptions to simplify their design, without a thorough implementation of other network layers. However, the implementation of a multi-beam MAC scheme on the well-known discrete event network simulator platforms (such as the Riverbed Modeler, NS3, QualNet) is challenging as it requires extensive changes and additions to various source code modules. In fact, the network protocols in these simulator packages have been mainly designed for omni-directional communication, and very few implementations of directional MAC and other network protocols exist in the literature. This paper presents a framework to implement a multi-beam directional MAC scheme in multi-hop wireless networks, by using the Wireless Suite of Riverbed Modeler. The detailed implementation procedures are described for multi-beam antenna module, multi-beam node model, concurrent packet transmission and reception, scheduling, collision avoidance, retransmission, and local node synchronization. These MAC modules and methodology can be very helpful to the researchers and developers for implementing the single-beam as well as multi-beam directional MAC and routing protocols in Riverbed Modeler.
... Ad hoc networks are the wireless networks in which communicating devices are connected in a specific fashion to form a network which is difficult to form in an extreme manner. The paper [22] discusses the use of smart antennas for such ad hoc networks. The advantage of using smart antennas is that there are multiple self-configuring beams with a high directivity. ...
The smart antenna technology is one of the upcoming technologies in the field of wireless communication. The use of smart antennas in wireless systems targets the improved capacity of the system and the increased coverage area. These antennas comprise of multiple antenna arrays with smart signal processing techniques like Direction of Arrival (DOA) estimation and then calculate beamforming vectors to track and locate the antenna beam on its target. This paper presents a theoretical study of smart antennas and their use for the performance enhancement of the high-frequency wireless systems. Then, adaptive array-based antenna systems, which one is a more effective approach to detect the mobile target is highlighted and discussed. They provide maximum Received Signal Strength (RSS) of the signal and mitigate any interference if present. There are various factors like cost, complexity, and requirements of the system, to be incorporated while selecting the adaptive array approach for smart antennas. The objective of the paper is to study smart antennas, the recent progress and the development of this technology in order to find out the further scope of research and development in this area.
... There is nothing smart in antenna, it is the antenna system which is smart and work intelligently for adaptive beamforming [7] [8]. Much of the research on smart antenna [10] has been focused on Direction of Arrival (DOA) calculation using MUSIC algorithm and its family [9]. Little work has been done on calculating DOA using ESPRIT algorithm. ...
... To increase the accuracy and resolution of the DOA estimation is one of the most important research work in the field of Smart Antenna. Estimating the DOA is a significant problem in array signal processing [9] [10]. ...
... The coverage range is merely the range of likely communication between mobile and base station [31]. Its capacity is quantify by the number of users that a system can support in a particular area [1,39,43]. ...
... Smart antenna array processing [6,41,42,[71][72][73][74][75] is based on the configuration of the spatial correlation matrix at the antenna array. In the design of smart antenna [43,44,76] techniques, system architecture, implementation and complexity limitations need to be considered. ...
... MANETs are the wireless networks where nodes can interconnect, whichever directly or indirectly deprived of any immovable substructure (fig. 14) [43]. Consequently, MANETs are predominantly imperative in locations, where the static substructure is not accessible, not confidential, too costly, or undependable. ...
Smart antenna is one of the most proficient and dominant technological innovations for maximizing capacity, improve quality, and coverage in wireless communications system. This work presents relevant comprehensive technical review of research work, unanswered questions, and untried methods on smart antennas technology for wireless communication systems. This also examines most of the significant improvements in the field of smart antennas technologies and the related fields in wireless communication systems. An evaluation of the analytical techniques for the theoretical analysis of adaptive beamforming algorithm, level of the system performance optimization approaches has been highlighted. Performance realistic evaluation and implementation cogent parameters areas for the deployment of smart antennas on the performance system in wireless communication systems have been also examined.
... Ad hoc networks are the wireless networks in which communicating devices are connected in a specific fashion to form a network which is difficult to form in an extreme manner. The paper [22] discusses the use of smart antennas for such ad hoc networks. The advantage of using smart antennas is that there are multiple self-configuring beams with a high directivity. ...
The smart antenna technology is one of the upcoming technologies in the field of wireless communication. The use of smart antennas in wireless systems targets the improved capacity of the system and the increased coverage area. These antennas comprise of multiple antenna arrays with smart signal processing techniques like Direction of Arrival (DOA) estimation and then calculate beamforming vectors to track and locate the antenna beam on its target. This paper presents a theoretical study of smart antennas and their use for the performance enhancement of the high-frequency wireless systems. Then, adaptive array-based antenna systems, which one is a more effective approach to detect the mobile target is highlighted and discussed. They provide maximum Received Signal Strength (RSS) of the signal and mitigate any interference if present. There are various factors like cost, complexity, and requirements of the system, to be incorporated while selecting the adaptive array approach for smart antennas. The objective of the paper is to study smart antennas, the recent progress and the development of this technology in order to find out the further scope of research and development in this area.
... The SBA operates as spatially selective filter, an effective approach in complex radio channel such as 802.11 WiFi network [7], in particular if implemented in circular polarization [8], [9]. ...
... This antenna system is able to detect the existence of the signal source automatically, forms the main beam in the direction of signals of interest, and produces notches in the direction of signals of interference [4]. An antenna array can not only increase the communications range, but also enable the smart antenna technology to be applied to optimize the system performance [5]. Factors affecting performance of adaptive antenna include both the adaptive algorithm and the structure of the antenna array. ...
This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using MUltiple SIgnal Classification (MUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.
... One efective way to implement SDMA is by the use of Switched Beam Antennas (SBA), i.e. an active antenna capable of selectively enabling the signal reception to be only from a specific angular region, [23]. This approach was conveniently employed to track target nodes in 2D scenarios, exploiting cylindrical antenna arrays [24], [25]. In [21], [26], [27], [28], the authors exploited a special sectorised SBA capable of SDMA for Direction of Arrival (DoA) estimation based on RSSI. ...
... In principle, in both cases the communication between the anchor and the target is possible regardless of the relative orientation. However, the cases CP-CP outperform CP-LP, as can be seen in estimating the signal standard deviation taken with a great number of messages (25,000). In the experimental case, it can be concluded that the CP-CP links, bring a CRB reduction due to about 2 to 3.5 times of the ratio between σ LP and σ CP . ...
In this paper, we present a distributed positioning system for indoor environment based on a mesh of compact independent anchor nodes. Each node is built of low-cost off-the-shelf components and operates as specialized access points capable of standard connectivity at 2.45 GHz. The key technology for the localization strategy is the switched beam antenna (SBA), which enables a space division multiple access (SDMA) paradigm. The coordinated operation of SBA-equipped anchor nodes constitutes a legacy unmodified IEEE 802.11 network which can exploit the multiplexing mechanism. The latter is the driving force of the estimation strategy, with the positional information obtained as the result of a maximum likelihood algorithm driven by the comparison of a real-time received signal strength indicator (RSSI) with the predicted signal level distribution, which can be estimated and stored without the need of lengthy offline measurement. The signal level prediction is based on a simple propagation model which is effective because benefits of both the elementary antenna radiation beams directivity and the circular polarization operation, two strong aids for the mitigation of the multipath impairment. In turn, these feature make the estimation procedure tolerant to noisy power measurements, hence particularly suitable for cost-effective solutions based on RSSI. Experimental validations demonstrate the performance of a network composed of four anchors arranged in a 2.6 × 3.8 m 2 mesh in a 6 × 7 m 2 office room, and dealing with a single target node. The mean error inside the mesh area is 63 cm while the mean error in the entire room is 1.1 m. Focusing on the cumulative distribution of the error, the 90th percentile value is 1 m considering only the mesh and 1.9 m for the entire room.
