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Full-Text Articles in Social and Behavioral Sciences
Antenna Selection Strategies For Mimo-Ofdm Wireless Systems: An Energy-Efficiency Perspective, Ngoc Phuc Le, Farzad Safaei, Le Chung Tran
Antenna Selection Strategies For Mimo-Ofdm Wireless Systems: An Energy-Efficiency Perspective, Ngoc Phuc Le, Farzad Safaei, Le Chung Tran
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we investigate antenna selection strategies for MIMO-OFDM wireless systems from an energy efficiency perspective. We first derive closed-form expressions of the energy efficiency and the energy efficiency- spectral efficiency (EE-SE) trade-off in conventional antenna selection MIMO-OFDM systems. The obtained results show that these systems suffer from a significant loss in energy efficiency. To achieve a better energy-efficiency performance, we propose an adaptive antenna selection method where both the number of active RF (radio frequency) chains and the antenna indices are selected depending on the channel condition. This selection scheme could be implemented by an exhaustive search technique …
A Survey Of Single And Multi-Hop Link Schedulers For Mmwave Wireless Systems, Jian Song, Kwan-Wu Chin
A Survey Of Single And Multi-Hop Link Schedulers For Mmwave Wireless Systems, Jian Song, Kwan-Wu Chin
Faculty of Engineering and Information Sciences - Papers: Part A
Wireless communication at 60. GHz, aka mmWave, provides extremely high data rates, i.e., several Gb/s. Moreover, devices have a much shorter transmission range as compared to those operating in the 2.4 and 5. GHz bands. Indeed, links can be treated as pseudo-wires with minimal interference leakage. As a result, future 60. GHz systems will have very high spatial reuse. This, however, is at the expense of high propagation loss, which can be overcome using directional or smart antennas. Another promising solution is to employ relays to boost the signal of weak links. In particular, if relays are properly selected, they …
Maximising Energy Efficiency In Antenna Selection Mimo Wireless Systems Subject To Qos Constraints, Ngoc Phuc Le, Farzad Safaei, Le Chung Tran
Maximising Energy Efficiency In Antenna Selection Mimo Wireless Systems Subject To Qos Constraints, Ngoc Phuc Le, Farzad Safaei, Le Chung Tran
Faculty of Engineering and Information Sciences - Papers: Part A
Energy-efficiency (EE) in antenna selection multi-input–multi-output (MIMO) systems over Nakagami-m fading channels is investigated. An EE metric is defined as the number of successfully received bits per unit of energy consumption, which takes into account several important system parameters such as channel coding and modulation. An optimisation problem that maximises the EE metric subject to an error-performance constraint is formulated. On the basis of an analysis of this problem, the optimal value of the average energy per transmitted data symbol is obtained, such that the EE in the system is maximised. Simulation results are provided to validate the analysis.
A Multi-Agent Framework For Packet Routing In Wireless Sensor Networks, Dayong Ye, Minjie Zhang, Yun Yang
A Multi-Agent Framework For Packet Routing In Wireless Sensor Networks, Dayong Ye, Minjie Zhang, Yun Yang
Faculty of Engineering and Information Sciences - Papers: Part A
No abstract provided.
Optimal Design For Energy-Efficient Per-Subcarrier Antenna Selection Mimo–Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Optimal Design For Energy-Efficient Per-Subcarrier Antenna Selection Mimo–Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we consider a novel optimal design for per-subcarrier antenna selection multi-input multi-output orthogonal frequency division multiplexing systems from an energy-efficiency perspective. The optimal number of antennas, i.e., the number of radio frequency chains, that needs to be built-in on a transmitter to achieve the maximum energy-efficiency is determined. Specifically, an optimization problem for maximizing the average energy-efficiency with respect to the number of antennas is formulated. To solve this optimization problem, we first derive a closed-form formula expressing the cost function (i.e., the average energy-efficiency) as a function of the number of antennas. Search algorithms are then …
On Using Wireless Power Transfer To Increase The Max Flow Of Rechargeable Wireless Sensor Networks, Tengjiao He, Kwan-Wu Chin, Sieteng Soh
On Using Wireless Power Transfer To Increase The Max Flow Of Rechargeable Wireless Sensor Networks, Tengjiao He, Kwan-Wu Chin, Sieteng Soh
Faculty of Engineering and Information Sciences - Papers: Part A
A key problem in Rechargeable Wireless Sensor Networks (WSNs) is determining the maximum amount of data that can be collected by a sink over a given time period. This maximum is constrained by link capacity and critically, by the available energy at each node. In this paper, we consider a novel approach to increase the maximum flow rate by exploiting recent advances in Wireless Power Transfer (WPT). Specifically, we deploy a finite number of WPT capable rovers next to bottleneck sensor nodes with the aim to increase the max flow rate of a WSN. We formulate a Mixed Integer Linear …
Novel Algorithms For Complete Targets Coverage In Energy Harvesting Wireless Sensor Networks, Changlin Yang, Kwan-Wu Chin
Novel Algorithms For Complete Targets Coverage In Energy Harvesting Wireless Sensor Networks, Changlin Yang, Kwan-Wu Chin
Faculty of Engineering and Information Sciences - Papers: Part A
This paper addresses the problem of maximizing the network lifetime of rechargeable Wireless Sensor Networks (WSNs) whilst ensuring all targets are monitored continuously by at least one sensor node. The objective is to determine a group of sensor nodes, and their wake-up schedule such that within a time interval, one subset of nodes are active whilst others enter the sleep state to conserve energy as well as recharge their battery. We propose a Linear Programming (LP) based solution to determine the activation schedule of sensor nodes whilst affording them recharging opportunities and at the same time ensures complete target coverage. …
Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Energy-Efficiency Analysis Of Per-Subcarrier Antenna Selection With Peak-Power Reduction In Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Faculty of Engineering and Information Sciences - Papers: Part A
The use of per-subcarrier antenna subset selection in OFDM wireless systems offers higher system capacity and/or improved link reliability.However, the implementation of the conventional per-subcarrier selection schememay result in significant fluctuations of the average power and peak power across antennas, which affects the potential benefits of the system. In this paper, power efficiency of high-power amplifiers and energy efficiency in per-subcarrier antenna selection MIMO-OFDM systems are investigated. To deliver the maximum overall power efficiency, we propose a two-step strategy for data-subcarrier allocation.This strategy consists of an equal allocation of data subcarriers based on linear optimization and peak-power reduction via cross-antenna …
Adaptive Antenna Selection For Energy-Efficient Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Adaptive Antenna Selection For Energy-Efficient Mimo-Ofdm Wireless Systems, Ngoc Phuc Le, Le Chung Tran, Farzad Safaei
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, we investigate energy-efficiency in antenna selection OFDM-based systems. We show that an OFDM system with conventional antenna selection approaches, including per-subcarrier selection (i.e., selecting antennas independently for each subcarrier) and bulk-selection (i.e., choosing the same antennas for all subcarriers), suffers from a significant loss in energy-efficiency. To achieve a better energy-efficiency performance, we propose an adaptive antenna selection scheme where both the number of active RF (radio frequency) chains and the antenna indices are selected depending on the channel condition. This selection scheme could be implemented by exhaustive search. Moreover, we develop an algorithm that achieves a …
Optimal Adaptive Wireless Body Area Networks For High Speed In Health Services, Miftadi Sudjai, Le Chung Tran, Farzad Safaei, Son Lam Phung
Optimal Adaptive Wireless Body Area Networks For High Speed In Health Services, Miftadi Sudjai, Le Chung Tran, Farzad Safaei, Son Lam Phung
Faculty of Engineering and Information Sciences - Papers: Part A
Adaptive ultra-wideband wireless body area networks have been proposed as one of feasible mHealth platforms offering a high-speed, robust mobile health service. The error performance of such sytems outperforms non-adaptive systems by up to 4 dB. To further improve the error performance, the optimization of adaptive parameters is investigated in this paper. Simulation results show that the proposed optimal adaptive systems achieves a 2 dB gain with respect to bit error rate (BER). This improvement is equivalent to extra reduction of the power consumption up to 37% in these networks, thus increasing the longevity and reliability of mHealth services.
Approximation Algorithm For Data Broadcasting In Duty Cycled Multi-Hop Wireless Networks, Dianbo Zhao, Kwan-Wu Chin
Approximation Algorithm For Data Broadcasting In Duty Cycled Multi-Hop Wireless Networks, Dianbo Zhao, Kwan-Wu Chin
Faculty of Engineering and Information Sciences - Papers: Part A
Broadcast is a fundamental operation in wireless networks. To this end, many past studies have studied the NP-hard, broadcast problem for always-on multi-hop networks. However, in wireless sensor networks, nodes are powered by batteries, meaning, they have finite energy. Consequently, nodes are required to have a low duty cycle, whereby they switch between active and sleep state periodically. This means that a transmission from a node may not reach all of its neighbors simultaneously. Consequently, any developed broadcast protocols must consider collisions and the wake-up times of neighboring nodes. Henceforth, this paper studies the minimum latency broadcast scheduling problem in …
Security Analysis Of A Distributed Reprogramming Protocol For Wireless Sensor Networks, Yong Yu, Jianbing Ni, Ying Sun
Security Analysis Of A Distributed Reprogramming Protocol For Wireless Sensor Networks, Yong Yu, Jianbing Ni, Ying Sun
Faculty of Engineering and Information Sciences - Papers: Part A
Reprogramming for wireless sensor networks is essential to upload new code or to alter the functionality of existing code. To overcome the weakness of the centralized approach of the traditional solutions, He et al. proposed the notion of distributed reprogramming where multiple authorized network users are able to reprogram sensor nodes without involving the base station. They also gave a novel distributed reprogramming protocol called SDRP by using identity-based signature, and provided a comprehensive security analysis for their protocol. In this letter, unfortunately, we demonstrate that SDRP is insecure as the protocol fails to satisfy the property of authenticity and …
Approximation Algorithms For Interference Aware Broadcast In Wireless Networks, Dianbo Zhao, Kwan-Wu Chin
Approximation Algorithms For Interference Aware Broadcast In Wireless Networks, Dianbo Zhao, Kwan-Wu Chin
Faculty of Engineering and Information Sciences - Papers: Part A
Broadcast is a fundamental operation in wireless networks and is well supported by the wireless channel. However, the interference resulting from a node's transmission pose a key challenge to the design of any broadcast algorithms/protocols. In particular, it is well known that a node's interference range is much larger than its transmission range and thus limits the number of transmitting and receiving nodes, which inevitably prolong broadcast. To this end, a number of past studies have designed broadcast algorithms that account for this interference range with the goal of deriving a broadcast schedule that minimizes latency. However, these works have …
Unitary Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb Wireless Communications, L C. Tran, A. Mertins, T A. Wysocki
Unitary Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb Wireless Communications, L C. Tran, A. Mertins, T A. Wysocki
Faculty of Engineering and Information Sciences - Papers: Part A
In a multiple-input multiple-output (MIMO), multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) system, coherent detection requires the transmission of a large number of symbols for channel estimation, thus reducing the bandwidth efficiency. For the first time, this paper proposes unitary differential space-time-frequency codes (DSTFCs) for MB-OFDM UWB communications, which increase the system bandwidth efficiency because no channel state information (CSI) is required. The proposed system would be useful when CSI is unavailable at the receiver, such as when the transmission of multiple channel estimation symbols is impractical or uneconomical. The coding and decoding algorithms for the proposed DSTFCs are …
On Improving Capacity And Delay In Multi Tx/Rx Wireless Mesh Networks With Weighted Links, Hung-Yi Loo, Sieteng Soh, Kwan-Wu Chin
On Improving Capacity And Delay In Multi Tx/Rx Wireless Mesh Networks With Weighted Links, Hung-Yi Loo, Sieteng Soh, Kwan-Wu Chin
Faculty of Engineering and Information Sciences - Papers: Part A
This paper considers the problem of deriving a link schedule for Time Division Multiple Access (TDMA)-based concurrent transmit/receive Wireless Mesh Networks (WMNs) that results in low end-to-end delays as well as high network capacity. We first propose a MAX-CUT heuristic approach, called Algo-2, that maximizes link activations in each slot of a super-frame. Algo-2 is shown to produce better network capacity as compared to existing heuristic approaches and significantly improves the super-frame length of an existing MAX-CUT approach that enforces 2-phase transmit-receive restriction - a node that transmits (receives) in slot i ≥ 1 is to become a receiver (transmitter) …
Wireless Indoor Localisation Using Received Signal Strength Fingerprinting With Context Aware Partitioning, Montserrat Ros, Brendan Schoots, Matthew D'Souza
Wireless Indoor Localisation Using Received Signal Strength Fingerprinting With Context Aware Partitioning, Montserrat Ros, Brendan Schoots, Matthew D'Souza
Faculty of Engineering and Information Sciences - Papers: Part A
Real-time indoor localisation tracking of people with unobtrusive, wearable sensors has valuable potential for a variety of applications such as remote monitoring and tracking of aged-care patients to improve their safety and other care aspects. There are no widely available or costeffective and ubiquitous wireless solutions like GPS for indoor localisation which require no prior infrastructure. Indoor localisation systems are available but most have difficulties operating in confined spaces or cannot localise to within small distances in real-time for moving objects as required for sport and health applications.
Hybrid Power Saving Technique For Wireless Sensor Networks, Asama Alshaibi, Peter Vial, Montserrat Ros
Hybrid Power Saving Technique For Wireless Sensor Networks, Asama Alshaibi, Peter Vial, Montserrat Ros
Faculty of Engineering and Information Sciences - Papers: Part A
In wireless communication, idle listening, receiving and transmitting are the main source of consumption of energy. This paper gives an overview of several techniques used for wireless networks. We incorporated PSM and PC to gain the advantage of PSM (reduce idle listening) and PC (reduce receiving and transmitting power) and implemented them in the IEEE 802.15.4 protocol. The results show that the new hybrid technique saves more power than PSM and PC individually. © 2012 IEEE.
The Ofdm-Idma Approach To Wireless Communication Systems, Li Ping, Qinghua Guo, Jun Tong
The Ofdm-Idma Approach To Wireless Communication Systems, Li Ping, Qinghua Guo, Jun Tong
Faculty of Engineering and Information Sciences - Papers: Part A
This article outlines the basic principles of OFDM-IDMA. Comparisons with other alternative technologies such as OFDM-CDMA and OFDMA are provided. Some attractive features of OFMD-IDMA are explained, including low-cost iterative multi-user detection, flexible rate adaptation, frequency diversity, and significant advantages regarding spectral and power efficiency. © 2007 IEEE.
On Short Forward Error-Correcting Codes For Wireless Communication Systems, Sheng Tong, Dengsheng Lin, Aleksandar Kavcic, Baoming Bai, Li Ping
On Short Forward Error-Correcting Codes For Wireless Communication Systems, Sheng Tong, Dengsheng Lin, Aleksandar Kavcic, Baoming Bai, Li Ping
Faculty of Engineering and Information Sciences - Papers: Part A
For real-time wireless communications, short forward error-correcting (FEC) codes are indispensable due to the strict delay requirement. In this paper we study the performance of short FEC codes. Reed-Solomon (RS) codes and concatenated zigzag (CZ) codes are chosen as representatives of classical algebraic codes and modern simple iterative decodable codes, respectively. Additionally, we use random binary linear codes as a baseline reference for comparison. Our main results (demonstrated by both simulation and ensemble distance spectrum analysis) are as follows: 1) Short RS codes are as good as random binary linear codes; 2) Carefully designed short low- density parity-check (LDPC) codes …
Using Rfid And Bluetooth For Localised Interaction With Wireless Embedded Internet Devices, Matthew D'Souza, Montserrat Ros, Adam Postula
Using Rfid And Bluetooth For Localised Interaction With Wireless Embedded Internet Devices, Matthew D'Souza, Montserrat Ros, Adam Postula
Faculty of Engineering and Information Sciences - Papers: Part A
Interaction with embedded devices can take on many forms. This paper describes the implementation of an interactive information network and intuitive mechanisms for the personal or home environment using Bluetooth wireless communication and Radio Frequency ID (RFID) tag technology. This approach combines the freedom associated with wireless communication and the ability to detect user commands by RFID location information. Embedded Access Points are described along with intuitive mechanisms including digital pen/paper, interactive information board and mobile computing devices. Specifically, the web access point facilitated an Internet over Bluetooth link and was found to provide an average data rate of 15.97kbps. …
A Multimedia Guidebook Implementation Using A Bluetooth Wireless Information Point Network, Matthew D'Souza, Adam Postula, Neil Bergmann, Montserrat Ros
A Multimedia Guidebook Implementation Using A Bluetooth Wireless Information Point Network, Matthew D'Souza, Adam Postula, Neil Bergmann, Montserrat Ros
Faculty of Engineering and Information Sciences - Papers: Part A
This paper describes the implementation of a Bluetooth Village Guide Book (VGB) scenario for use in the Kelvin Grove Urban Village located in Brisbane, Australia. An Information Point Station Network (IPSN) was developed, along with software for two types of mobile computing devices. The implementation consists of several Information Point Stations (IPSs) placed at locations of significance, with access to information items on a centralized server. Once a user is registered on the network, he/she is given the opportunity to experience context and eventually user aware information on demand and in various multimedia formats. These information items are selected by …
Using Wireless Sensors As Selection Devices For A Multimedia Guidebook Scenario, Montserrat Ros, Matthew D'Souza, Michael Chan, Konstanty Bialkowski, Adam Postula, Neil Bergmann, Andras Toth
Using Wireless Sensors As Selection Devices For A Multimedia Guidebook Scenario, Montserrat Ros, Matthew D'Souza, Michael Chan, Konstanty Bialkowski, Adam Postula, Neil Bergmann, Andras Toth
Faculty of Engineering and Information Sciences - Papers: Part A
This paper describes the implementation of a wireless sensor network for a multimedia guidebook scenario incorporating a pointer-sensor system for the selection of locality-aware information. An Information Point Station Network (IPSN) was developed and consists of several Information Point Stations (IPSs) placed at locations of significance, with access to information items on a centralized server. In the multimedia guidebook scenario, a user selects a particular information item to view, either by way of a menu system appearing on their mobile computing device (MCD) or a more intuitive pointer-sensor system as described in this paper. Laser sensors are placed next to …
A Bluetooth Wireless Network Infrastructure For Multimedia Guidebooks On Mobile Computing Devices, Matthew D'Souza, Montserrat Ros, Adam Postula, Neil Bergmann
A Bluetooth Wireless Network Infrastructure For Multimedia Guidebooks On Mobile Computing Devices, Matthew D'Souza, Montserrat Ros, Adam Postula, Neil Bergmann
Faculty of Engineering and Information Sciences - Papers: Part A
This paper describes the implementation of a Bluetooth Village Guide Book (VGB) scenario for use in the Kelvin Grove Urban Village located in Brisbane, Australia. An Information Point Station Network (IPSN) was developed, along with software for two types of mobile computing devices. The implementation consists of several Information Point Stations (IPSs) placed at locations of significance, with access to information items on a centralized server. Once registered, the user is given the opportunity to experience context-aware information on demand and in various multimedia formats. These information items are selected by the user, either by way of a menu system …