International Journal of Ultra Wideband Communications and Systems (8 papers in press)
Performance Evaluation of IR-UWB Detectors and Fusion Techniques for UWB Transceiver Platforms
by Vijaya Yajnanarayana, Peter Handel
Abstract: In this paper, we analyze the performance of a multi-pulse impulse radio based ultra-wideband (IR-UWB) detector in an AWGN setting and provide different fusion strategies for fusing these detector outputs. To enable the transceiver to be used for multiple applications, the designers have different types of detectors such as energy detectors, amplitude detectors, etc., built in to a single transceiver architecture. In order to get early insight into theoretically achievable performance of these fusion techniques, we assess the performance of these fusion techniques for commonly used detector types like matched filter, energy detector and amplitude detector under a Gaussian assumption. The proposed methods are valid for ultra short distance communication and in UWB systems operating in millimeter wave (mmWave) band with high directivity gain. In this paper, we derive the detection performance equation for each of the detectors in terms of false alarm rate, shape of the pulse, and number of UWB pulses used in the detection and apply these in the fusion algorithms. We show that the performance can be improved by approximately 4 dB in terms of signal to noise ratio (SNR) for high probability of detection of a UWB signal (>95%), by fusing decisions from multiple detector types compared to a standalone energy detector, in a practical scenario.
Keywords: Ultra Wideband (UWB); Time of Arrival (TOA); UWB ranging; Neyman-Pearson test; Sensor Networks.
An Indoor Path Loss Model for Wireless Sensor Networks
by Mohammad Abdel-Rahim, Mohamed Habaebi, Jalel Chebil, Aisha Hashim, Musse Ahmed, M.D. Rafiqul Islam, Alhareth Zyoud
Abstract: In this paper, path loss measurements were conducted and a path loss model was proposed for Wireless Sensor Networks (WSNs) operating in indoor environment. This is done with a view to study transmit power requirements in indoor application of WSNs. The proposed model is a hybrid of the two-ray ground reflection model and the log-normal model and considers frequency and three-dimensional link trajectory as key parameters in evaluating path loss. The study highlights the effect of height on path loss exponent by means of various measurements taken in indoor environment. Comparison with the empirical data and other models in the literature was conducted and had very favourable results for the proposed model.
Keywords: channel models; indoor environments; path loss exponent; ZigBee; empirical models.
CPW - Fed Dodecagon Ring Shape Antenna for Ultra Wide Band Application
by Amar Sharma, Puneet Khanna, Anil Kumar Singh, Arun Kumar
Abstract: The paper presents a coplanar waveguide (CPW) Fed compact ultra wideband (UWB) dodecagon ring shape microstrip antenna. The proposed antenna consists of dodecagon ring radiating patch in place of a conventional annular ring microstrip antenna (ARMSA) to achieve UWB. The proposed antenna is simulated through Ansofts High Frequency Structure Simulator (HFSS v 14.0). Measured result shows good agreement with the simulated results. The prototype is taken with dimensions 47 mm
Keywords: Dodecagon; CPW-Fed; High Gain; UWB Microstrip Antenna.
Wireless Sensor Network Localization using New Heuristic Optimization Algorithms
by Mohammad Sadeghian Kerdabadi, Farhad Parsaie Nejad, Reza Ghazizadeh, Hamid Farrokhi
Abstract: The localization algorithms for WSNs can be divided into range-free and range-based algorithms based on whether it is required to know the actual distances between the nodes or the distance is approximated based on the connectivity information. The range-free algorithms usually have higher localization error compared to the range based algorithms but it is simple to implement. DV-Hop is a typical range-free localization algorithm employing hop-distance estimation. In this paper, we present three improved DV-Hop localization approaches based on Imperialist Competitive Algorithm (ICA-DV-Hop), Gravitational Search Algorithm (GSA-DV-Hop) and Inclined Planes System Optimization (IPO-DV-Hop). In other words, the localization optimization problem is solved using heuristic algorithms to enhance the localization results of DV-Hop. The proposed approaches have been compared with particle swarm optimization (PSO), Genetic Algorithm (GA) and original DV-Hop method. The simulation results indicate that the proposed algorithms can reduce the localization error and achieve higher positioning accuracy.
Keywords: Wireless Sensor Networks; Localization; Heuristic Algorithms; DV-Hop; Gravitational Search Algorithm (GSA).
Energy Efficiency Performance Evaluation For Multiband-OFDM UWB Cross-layer Design
by HODA CHIHI
Abstract: Energy consumption is an important criterion that needs great attention as it is the requirement of energy efficiency (EE) improvement. In this regard, we analyze the joint association between physical layer through modulation and coding scheme (MCS) and data link layer toward truncated Hybrid Automatic Repeat reQuest (HARQ) type I retransmission protocol into Multiband Orthogonal Frequency Division Multiplexing Ultra-WideBand (MB-OFDM UWB) systems. This paper investigates the overall energy expenditure per bit in cross-layer design. The total energy expenditure per bit of information is investigated following an adopted energy consumption model. The idea is about energy per bit diminishing in terms of Packet Error Rate (PER) under the respect of an accurate energy consumption model. Computer results show a comparison between different MCS levels in terms of energy expenditure per bit of information.
Keywords: Energy efficiency;Cross-layer design; MB-OFDM; UWB; HARQ; MCS.
Key Shaped Planar UWB Monopole Antenna with Dual Band-Notch Characteristics
by Yogendra Awasthi, Manish Sharma, Himanshu Singh, Raj Kumar, Sarita Kumari
Abstract: In this paper, dual vertical cross-elliptical radiating elements dual-notched ultra-wideband antenna (UWB) is proposed. The proposed antenna is compact in size (18 20 mm2 = 360mm2) with combination of two ellipse and modified ground plane so as to cover UWB impedance bandwidth. There is a close agreement between the simulated and the measured results like return loss and VSWR of the proposed antenna where measured results also covers impedance UWB bandwidth from 2.84GHz to 10.83GHz which validates FCC standard UWB bandwidth from 3.1GHz to 10.6GHz. Moreover the two Notched bands i.e. WiMAX (3.30-3.80GHz) along with C-Band (3.80-4.20GHz) and WLAN-IEEE 802.11a (5.15-5.825GHz) band stopped so that the interference is eliminated. Proposed Antenna is verified by measuring gain and radiation characteristics which exhibits nearly omni-directional pattern in the H-plane and monopole like pattern in E-plane of UWB bandwidth.
Keywords: Key Shape; ultra wideband antenna; monopole; dual notch; WiMAX; WLAN.
Novel and simple monopole blade antenna with ultra-wide bandwidth for avionics applications
by Seyed Ramin Emadian, Javad Ahmadi-Shokouh
Abstract: In this paper a novel low profile radome enclosed monopole blade antenna is designed, fabricated and tested with ultra wide bandwidth for L-band, S-band and C-band applications. The antenna consists of a tapered blade mounted on a rectangular ground plane. Several circular slots are etched from the tapered blade to improve the bandwidth of the antenna. The antenna has a compact size, aero- dynamic shape and light weight and shows omnidirectional radiation patterns in azimuth plane, therefore it is suitable for UAV (unmanned aerial vehicles) and avionics applications. The simulated and measurement results are presented and discussed in the paper and they are in close agreement with each other.
Keywords: monopole blade antenna. ultrawideband. circular slots. Avionic systems. radiation patterns.
Queueing Analysis of Ultra-wideband Medium Access Control Protocol
with Finite Buffer
by Hassan Al-Mahdi
Abstract: Ultra-wideband (UWB) communication has recently emerged as a technology that offers high data rate services for future wireless personal area networks. Due to its high bandwidth, it is substantial to design medium access control (MAC) protocols that perfectly utilize the available shared bandwidth offered by UWB technology. The available bandwidth may be used as a single band or as several bands. Recently, the multi-band MAC protocols of the UWB communication have received a great attention in research domain. This paper introduces an extensive 4-dimensional Markov chain queueing model to investigate the performance of MAC protocol that was proposed in literature in terms of system occupancy, waiting time, throughput, packet loss and blocking probability. Furthermore, we modify the analyzed protocol by attaching a finite buffer inside every node.
Our motivation is to precisely estimate packets collision probability due to randomly selection of receivers or bands. Besides introducing the finite buffer, our queuing model reflects the system behavior in-depth. Next, we validate the obtained analytic results using discrete-event simulation. Finally, we introduce an outline of a proposal to eliminate the randomness of selecting receivers and bands.
Keywords: Ultra-wideband; Queueing network; performance evaluation; medium access control; ad hoc networks.