Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Computer Engineering
Optimal Receiver For Space Time Spreading Across A Time Hopping Ppm Over Ultra Wideband Saleh-Valenzuela Mimo Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki
Optimal Receiver For Space Time Spreading Across A Time Hopping Ppm Over Ultra Wideband Saleh-Valenzuela Mimo Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
This paper outlines a technique which can use multiple transmit antennas to send more than one binary bit using the same number of transmit antennas over a single transmission. It uses Ultra Wideband orthogonal pulse position modulation to achieve this, with the receiver employing a Rake receiver and a Maximum Ratio Combiner optimal detector. This is done over a Space Time Spreading Time Hopping Ultra Wideband Pulse Position Modulation system assuming a rich multipath Saleh-Valenzuela MIMO channel model. Simulation results indicate that a significant gain can be achieved compared with other proposed schemes utilising multiple transmit antennas for Ultra Wide …
Scalability Of Manet Routing Protocols For Heterogeneous And Homogenous Networks, Huda Al Amri, Mehran Abolhasan, Tadeusz Wysocki
Scalability Of Manet Routing Protocols For Heterogeneous And Homogenous Networks, Huda Al Amri, Mehran Abolhasan, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
In Mobile Ad hoc Network (MANET), mobility, traffic and node density are main network conditions that significantly affect the performance of routing protocols. Much of the previous researches in MANET routing have focused on developing strategies, which suit one specific networking scenario. Therefore, there is no existing protocol that can work well in all different networking scenarios. This paper reviews characteristics of each different classes of routing protocols. Moreover, most of current routing protocols assume homogeneous networking conditions where all nodes have the same capabilities and resources. Although homogenous networks are easy to model and analysis, they exhibits poor scalability …
Closed-Form Derivations Of Isi And Mui For Time-Reversed Ultra Wideband, K. Popovski, Beata J. Wysocki, Tadeusz Wysocki
Closed-Form Derivations Of Isi And Mui For Time-Reversed Ultra Wideband, K. Popovski, Beata J. Wysocki, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Through transmitter pre-filtering, a time reversed UWB system is capable if harnessing a multipath channel to achieve temporal and spatial focusing. Unfortunately, large RMS channel delay spread leads to significant intersymbol and multiuser interference. This paper presents closed-form expressions for self and multi-user interference for a UWB system utilizing a time-reversed approach. The influence of user multiplexing codes is taken to account through incorporation of a ‘separation probability’, which characterizes a family of hopping sequences. The standardized IEEE 802.15.3a channel model is applied, and the derived performances are compared with that of a simulated time hopped time-reversed UWB system.
Collaborative Image Transmissions Based On Region And Path Diversity In Wireless Sensor Network, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, Hsiao-Hwa Chen
Collaborative Image Transmissions Based On Region And Path Diversity In Wireless Sensor Network, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, Hsiao-Hwa Chen
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Many Sensor applications such as monitoring and surveillance may require image sensor array to conduct collaborative image transmissions in Wireless Sensor Networks (WSN). The large size image transmissions cause bottlenecks in WSN due to the limited energy resources and network capacity. In this paper, we propose a collaborative transmission scheme for image sensors to utilize inter-sensor correlations to decide transmission patterns based on transmission path diversities, which achieves minimal energy consumption, balanced sensor lifetime and required image quality. This optimization scheme not only allows each image sensor to transmit optimal fractions of the overlapped images through appropriate transmission paths in …
Design Of A 1.8v 8-Bit 500msps Folding-Interpolation Cmos A/D Converter With A Folder Averaging Technique, Dongjin Lee, Jaewon Song, Jongha Shin, Sanghoon Hwang, Minkyu Song, Tad Wysocki
Design Of A 1.8v 8-Bit 500msps Folding-Interpolation Cmos A/D Converter With A Folder Averaging Technique, Dongjin Lee, Jaewon Song, Jongha Shin, Sanghoon Hwang, Minkyu Song, Tad Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
In this paper, a CMOS analog-to-digital converter (ADC) with an 8-bit 500MSPS at 1.8V is designed. The architecture of the proposed ADC is based on a Folding ADC with a cascaded-folding and a cascaded-interpolation structure. A self-linearized preamplifier with source degeneration technique and a folder averaging technique for the high-performance are introduced. Further, a novel auto-switching encoder is also proposed. The chip has been fabricated with 0.18μm 1-poly 5-metal CMOS technology. The active chip area is 0.79mm2 and it consumes about 200mW at 1.8V power supply. The DNL and INL are within ±0.6/±0.6LSB, respectively. The measured result of SNDR …
A Small Chip Area 12-B 300ms/S Current Steering Cmos D/A Converter Based On A Laminated-Step Layout Technique, Byungseung Lee, Byungill Kim, Juneseok Lee, Sanghoon Hwang, Minkyu Song, Tad Wysocki
A Small Chip Area 12-B 300ms/S Current Steering Cmos D/A Converter Based On A Laminated-Step Layout Technique, Byungseung Lee, Byungill Kim, Juneseok Lee, Sanghoon Hwang, Minkyu Song, Tad Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
A 12-b 300MSPS Current-Steering DAC with 0.13um CMOS technology is presented. In order to reduce the chip area, a laminated-step layout technique is proposed. Based on this technique, the occupied DAC core size is only 0.26mm2 even in 12-b resolution. Further, a current auto-averaging technique, an output impedance enhancement circuit, and the novel latched switching cell logic are discussed to keep the desired 12- b DAC performance. The measured results are within ±1LSB for DNL. The measured SFDR is 70dB under Nyquist output frequency with 50mW power dissipation at 3.3V power supply.
A Simple Orthogonal Space-Time-Polarization Block Code, B. J. Wysocki, Tadeusz Wysocki, J. Seberry, S. Spence Adams, H. Sharif
A Simple Orthogonal Space-Time-Polarization Block Code, B. J. Wysocki, Tadeusz Wysocki, J. Seberry, S. Spence Adams, H. Sharif
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
This letter proposes a simple but highly efficient technique to jointly utilize space, time, and polarization diversities. The technique is based on extending orthogonal space-time block codes into the quaternion domain and utilizing a description of the dual-polarized signal by means of quaternions, which are a generalization of complex numbers. In the given example, the achievable performance gain for two transmit and one receive antennas is approximately 6 dB at a bit error rate of 10-4 when compared with the Alamouti code.
Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb Communications, L. C. Tran, A. Mertins, Tadeusz A. Wysocki
Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb Communications, L. C. Tran, A. Mertins, Tadeusz A. Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
The paper examines the implementation of Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) to increase data rates and error performance in recently proposed STFC Multiband OFDM Ultra Wideband (MB-OFDM UWB) communications systems. It is shown that, an order-4 QOSTFC not only can provide the full rate, but also may provide significantly better error performance, compared to the conventional MB-OFDM (without STFCs), and considerably better error performance, compared to order-4, orthogonal STFC MBOFDM, without increasing the total transmission power.
A Bayesian Multilevel Modeling Approach For Data Query In Wireless Sensor Networks, Honggang Wang, Hua Fang, Kimberly A. Espy, Dongming Peng, Hamid Sharif
A Bayesian Multilevel Modeling Approach For Data Query In Wireless Sensor Networks, Honggang Wang, Hua Fang, Kimberly A. Espy, Dongming Peng, Hamid Sharif
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
In power-limited Wireless Sensor Network (WSN), it is important to reduce the communication load in order to achieve energy savings. This paper applies a novel statistic method to estimate the parameters based on the real-time data measured by local sensors. Instead of transmitting large real-time data, we proposed to transmit the small amount of dynamic parameters by exploiting both temporal and spatial correlation within and between sensor clusters. The temporal correlation is built on the level-1 Bayesian model at each sensor to predict local readings. Each local sensor transmits their local parameters learned from historical measurement data to their cluster …