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University of Nebraska - Lincoln
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
- Keyword
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- UWB (3)
- Pre-rake equalization (2)
- TCM (2)
- TTCM (2)
- Time-reversed (2)
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- BER (1)
- Direct Sequence (1)
- Diversity methods (1)
- Hyperbolic congruence (1)
- IEE 802.16e Wireless Networks (1)
- MIMO (1)
- MRC (1)
- Mobile communications (1)
- Multiple- input multiple-output (MIMO) systems (1)
- Nonbinary-Turbo (1)
- Nonbinary-turbo (1)
- PRake (1)
- Polarization (1)
- Railroad Mobile Multi-hop Test Bed (1)
- SISO (1)
- SRake (1)
- Saleh- Valenzuela (1)
- Space Time Spreading (1)
- Time Hopping (1)
- Walsh-Hadamard (1)
Articles 1 - 10 of 10
Full-Text Articles in Computer Engineering
Energy-Constrained Distortion Reduction Optimization For Wavelet-Based Coded Image Transmission In Wireless Sensor Networks, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Hsiao-Hwa Chen
Energy-Constrained Distortion Reduction Optimization For Wavelet-Based Coded Image Transmission In Wireless Sensor Networks, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Hsiao-Hwa Chen
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Image transmissions in Wireless Multimedia Sensor Networks (WMSNs) are often energy constrained. They also have requirement on distortion minimization, which may be achieved through Unequal Error Protection (UEP) based communication approaches. In related literature with regard to wireless multimedia transmissions, significantly different importance levels between image-pixel-position information and image-pixel-value information have not been fully exploited by existing UEP schemes. In this paper, we propose an innovative image-pixel-position information based resource allocation scheme to optimize image transmission quality with strict energy budget constraint for image applications in WMSNs, and it works by exploring these uniquely different importance levels among image data …
Development And Performance Evaluation Of A Flexible, Low Cost Manet, M. Abolhasan, B. Hagelstein, J.C-P. Wang, D.R. Franklin, F Safaei, Tadeusz Wysocki
Development And Performance Evaluation Of A Flexible, Low Cost Manet, M. Abolhasan, B. Hagelstein, J.C-P. Wang, D.R. Franklin, F Safaei, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Performance evaluations of multi-hop ad hoc network routing protocols have been primarily conducted through analytic and simulation-based studies, which frequently fail to accurately predict real-world performance and behaviour. One reason for this is the challenge in developing low cost, representative test beds with the degree of flexibility and mobility required. We have developed a Portable Wireless Ad hoc Node (PWAN) device which establishes multi-hop routes using the OLSR routing protocol. The PWAN’s performance has been investigated using two test bed configurations to evaluate its capacity under conditions of high node density in a short-range, multi-hop environment. Our results illustrate that …
Performance Analysis Of Multi-Hop Ieee 802.11 Dcf Backhaul Networks, Puttipong Mahasukhon, Hamid Sharif, Michael Hempel, Ting Zhou, Wei Wang, Tadeusz Wysocki
Performance Analysis Of Multi-Hop Ieee 802.11 Dcf Backhaul Networks, Puttipong Mahasukhon, Hamid Sharif, Michael Hempel, Ting Zhou, Wei Wang, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Because of the wide deployment of 802.11 equipments in the past decade, current applications are not limited anymore to only single Access Points (AP) deployments for indoor usage, but have been extended to multi-hop networks to fulfill the need of high speed connectivity in mobile environments, where the analysis of multi-hop networks is extremely complicated. The behavior of an AP is dependent not only on its neighbors’ behavior, but also on the behavior of other hidden nodes. In this paper, we provide an accurate and verified multi-hop wireless backhaul analysis for performance of IEEE 802.11 DCF in terms of the …
The Theory Of Quaternion Orthogonal Designs, Jennifer Seberry, Ken Finlayson, Sarah Spence Adams, Tadeusz Wysocki, Tianbing Xia, Beata Joanna Wysocki
The Theory Of Quaternion Orthogonal Designs, Jennifer Seberry, Ken Finlayson, Sarah Spence Adams, Tadeusz Wysocki, Tianbing Xia, Beata Joanna Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Over the past several years, there has been a renewed interest in complex orthogonal designs for their application in space–time block coding. Motivated by the success of this application, this paper generalizes the definition of complex orthogonal designs by introducing orthogonal designs over the quaternion domain. This paper builds a theory of these novel quaternion orthogonal designs, offers examples, and provides several construction techniques. These theoretical results, along with the results of preliminary simulations, lay the foundation for developing applications of these designs as orthogonal space–time-polarization block codes.
Non-Optimal Receiver For Space Time Spreading Across A Time Hopping Over Ultra Wideband Ppm, Peter Vial, Beata Wysocki, Tadeusz Wysocki
Non-Optimal Receiver For Space Time Spreading Across A Time Hopping Over Ultra Wideband Ppm, Peter Vial, Beata Wysocki, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
A novel non-optimal chip based technique is proposed to use two antennas to transmit data across a Direct Sequence Time Hopping Ultra Wideband dual antenna wireless communication system to a single receiver. The spread data is sent over the independent channels using the Space Time Spreading technique to encode the chips which are sent on each antenna simultaneously. A hard decision is made at each chip of the spreading code received based on the known Channel State Information which Pulse Position Modulated signal was received from each antenna. The paper shows that by adapting the Space Time Spreading technique to …
Truncated Hyperbolic Mapping For Non-Binary Turbo Coding In Uwb, K. Popovski, Tadeusz Wysocki, B. J. Wysocki
Truncated Hyperbolic Mapping For Non-Binary Turbo Coding In Uwb, K. Popovski, Tadeusz Wysocki, B. J. Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
The combination of user multiplexing and data encoding within Ultra Wideband systems has been proposed to improve bit error performance. Relative to conventional binary coding, this technique has shown to reduce error rates in scarcely populated systems. Where non-binary turbo coding modulates data to form an integer sequence, a random mapping is generally applied to develop a time hopping sequence. This paper explores the possibility of mapping through the application of truncated hyperbolic congruence codes. Comparative results against a random mapping indicate an improvement in system performance for higher turbo iteration levels in the receiver. Transceiver architecture is based upon …
Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, L. C. Tran, A. Mertins, Tadeusz Wysocki
Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, L. C. Tran, A. Mertins, Tadeusz Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Though cooperative communication has been intensively examined for general wireless systems, such as mobile and ad-hoc networks, it has been almost unexplored in the case of Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB). This paper proposes a framework of cooperative communication in such systems where nodes are equipped with only one antenna. Simulation results show that cooperative communication might, in some cases, provide better error performance than non-cooperative communication without any additional transmission power.
Combined User Multiplexing And Data Modulation Through Non-Binary Turbo Codes For Uwb, K. Popovski, Tadeusz Wysocki, B. J. Wysocki
Combined User Multiplexing And Data Modulation Through Non-Binary Turbo Codes For Uwb, K. Popovski, Tadeusz Wysocki, B. J. Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
With significant research being conducted in Ultra Wideband communications to increase error performance, this paper proposes a combination of user multiplexing and data encoding to achieve a BER improvement. Through the use of non-binary turbo coding, data is modulated to form a time hopping code which is applied to a time-reversed UWB system. Comparative results with conventional binary coding are given, showing the possibility for BER improvements in systems with a low number of users. Slight performance degradations for a large number of users exist. The effects of a user applying turbo coding on other users not applying forward error …
Artificial Immune System Based Image Pattern Recognition In Energy Efficient Wireless Multimedia Sensor Networks, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, J. Wegiel, D. Nguyen, R. Bowne, C. Backhaus
Artificial Immune System Based Image Pattern Recognition In Energy Efficient Wireless Multimedia Sensor Networks, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, J. Wegiel, D. Nguyen, R. Bowne, C. Backhaus
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
In Wireless Multimedia Sensor Networks (WMSNs), low cost Complementary Metal Oxide Semiconductor (CMOS) camera sensors may only produce low resolution images due to hardware limitations. However, super-resolution images may be constructed from these low resolution images in a multiple sensor network, improving object pattern recognition success rates. There is a critical image recognition challenge in these reconstructed superresolution images for accuracy, complexity and limited energy resource in wireless sensor networks. Artificial Immune Systems (AIS), in particular those possessing algorithmic efficiency for image pattern differentiation, categorization and recognition, have potential advantages in low-cost automated monitoring and object detection applications. In this …
Throughput Vs. Distance Tradeoffs And Deployment Considerations For A Multi-Hop Ieee 802.16e Railroad Test Bed, Wei Wang, Hamid Sharif, Ting Zhou, Puttipong Mahasukhon
Throughput Vs. Distance Tradeoffs And Deployment Considerations For A Multi-Hop Ieee 802.16e Railroad Test Bed, Wei Wang, Hamid Sharif, Ting Zhou, Puttipong Mahasukhon
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Throughput vs. distance analysis and coverage requirements are critical issues in planning wireless network deployments. With the recent availability of IEEE 802.16e and its promise of larger coverage areas for high-speed data communication, evaluating it in a real-world environment is very important to us in our ongoing study of standards based wireless technologies for the Federal Railroad Administration (FRA). In this paper, we present results obtained with our IEEE 802.16e module for NS-2, particularly throughput vs. distance performance, and its consideration for designing a real-world multi-hop IEEE 802.16e testbed. Firstly, a quantitative analysis of throughput vs. distance performance is conducted …