Traffic offloading among coexisting heterogeneous radio access technologies (RATs), i.e., inter-RAT offloading, is considered to be an effective strategy for enhancing the capacity of wireless networks and reducing the power consumption... more
Traffic offloading among coexisting heterogeneous radio access technologies (RATs), i.e., inter-RAT offloading, is considered to be an effective strategy for enhancing the capacity of wireless networks and reducing the power consumption of both base stations (BSs) and mobile stations (MSs). To fully utilize inter-RAT offloading advantages, a mobility-aware evaluation is needed, which takes into account the combined effects of mobility and MS and BS spatial distributions on the performance gains. This paper proposes a novel analytical model that accurately describes MS mobility dynamics in heterogeneous wireless networks, while conveying detailed information on its location. In addition, this paper derives an analytical expression for calculating the packet loss probability for orthogonal-frequency-division-multiple-access (OFDMA)-based networks. Taking users' mobility and spatial distribution into account, this paper develops a Markovian-based framework for evaluating inter-RAT offloading performance. The accuracy of the proposed mobility model and the efficacy of the proposed performance evaluation framework are validated. Results show that MS mobility and vertical handover (VHO) cost significantly affect inter-RAT offloading performance, and ignoring their effects could lead to an inaccurate evaluation. When the effects of MS mobility and VHO cost on the performance are ignored, utilizing inter-RAT offloading decreases the packet loss probability by 9% and saves energy by 6%. However, accounting for these effects results in a 32% increase in the packet loss probability evaluation and a 64% increase in the energy consumption evaluation.
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Cyclostationary detector (CSD) is one of the spectrum sensing techniques used in cognitive radio. Although it has a superior performance in Gaussian environments, its performance severely deteriorates in non-Gaussian environments. This... more
Cyclostationary detector (CSD) is one of the spectrum sensing techniques used in cognitive radio. Although it has a superior performance in Gaussian environments, its performance severely deteriorates in non-Gaussian environments. This paper proposes a novel dynamic CSD-based algorithm that jointly utilizes the generalized seasonal block bootstrap (GSBB) re-sampling techniques and the cyclic mismatch property to improve the performance of the CSD detector in non-Gaussian environments. The novelty of this algorithm lies in the fact that it does not require prior knowledge about the noise distribution nor does it require noise-only samples to set the detection threshold. Simulation results show that the proposed algorithm maintains the required probability of false alarm at 10% under Gaussian and non-Gaussian noise, unlike its counterparts which increase the false alarm probability up to 38% under non-Gaussian noise.
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⎯This paper presents the theoretical analysis for Noncoherent multi-tone code division multiple access (MT-CDMA) system in terms of average bit error rate (BER). The system uses differential binary phase shift keying (DBPSK) modulation... more
⎯This paper presents the theoretical analysis for Noncoherent multi-tone code division multiple access (MT-CDMA) system in terms of average bit error rate (BER). The system uses differential binary phase shift keying (DBPSK) modulation and post-detection diversity combining, considering slowly Rician fading and frequency selective channel in the indoor environment. Post-detection diversity is considered because it non-coherently combines the received signals from different diversity branches after differential detection. Here, the influence of the order of diversity and number of tones is studied for given bandwidth (BW), bit rate and transmitter power.
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This paper proposes a quality of servicebased multiple-route ad hoc on-demand distance vector (QoS-MRAODV) routing protocol for achieving and maintaining QoS in mobile ad hoc networks (MANETs). The QoS-MRAODV protocol supports one active... more
This paper proposes a quality of servicebased multiple-route ad hoc on-demand distance vector (QoS-MRAODV) routing protocol for achieving and maintaining QoS in mobile ad hoc networks (MANETs). The QoS-MRAODV protocol supports one active QoS-based primary route ...
Research Interests: Computer Science, Mobile Ad Hoc Networks, Routing protocols, Mobile Ad Hoc Network, Ad Hoc Networks, and 9 moreQuality of Service, Resource Management, Ad hoc On-Demand Distance Vector, Routing Protocol, Route Discovery, Perforation, Network Topology, Bandwidth, and Electrical and Computer Engineering
We analyze the envelope correlation of two resolvable paths belonging to replicas of a wide-band signal modulated on two subcarriers in a Rayleigh fading channel. The results indicate that the frequency correlation of resolvable paths not... more
We analyze the envelope correlation of two resolvable paths belonging to replicas of a wide-band signal modulated on two subcarriers in a Rayleigh fading channel. The results indicate that the frequency correlation of resolvable paths not only depends on the RMS delay spread but also on the signal bandwidth. The results can be used in appropriately choosing the subcarriers of direct sequence spread spectrum (DS-SS) communication systems employing frequency diversity for wide-band signals. For this analysis the authors assume a wide-sense stationary uncorrelated scattering (WSSUS) mobile radio channel in which the propagation takes place by single scattering
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In next-generation wireless networks, high data rates, improvement of Spectral Efficiency (SE), meeting the Quality of Service (QoS) requirements, increasing Energy Efficiency (EE), reducing cost, and lower complexity of cellular networks... more
In next-generation wireless networks, high data rates, improvement of Spectral Efficiency (SE), meeting the Quality of Service (QoS) requirements, increasing Energy Efficiency (EE), reducing cost, and lower complexity of cellular networks systems have become essential design metrics. Use of resource allocation and interference mitigation techniques achieve these targets, especially for users located in the cell edge region. FFR schemes with relays are used to minimize the impact of ICI in Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks and to enhance the QoS. The frequency patterns (sets) in the FFR scheme are designed such that the interference from adjacent cells is minimized. Instead of using the cell system with Frequency Reuse Factor (FRF) of 1 $\mathbf{TRF} \pmb{=1}$), $\mathbf{FRF} \pmb{=3}$, and $\mathbf{FRF} \pmb{=(1,3)}$, this paper proposes new frequency patterns for $\mathbf{FRF} \pmb{=(1,7/3)}$ using (7,3,1) difference set and $\mathbf{FRF} \pmb{=(1,7/4)}$ using (7,4,2) difference set to provide an enhancement of the system performance in terms of SE, EE, Signal-to-Interference plus Noise Ratio (SINR), Cumulative Distribution Function (CDF) of SINR of the received signal, and Outage Probability (OP). Simulation results show that the proposed schemes have more significant ICI reduction for cell edge users compared to those of previous work.
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Inter-Cell Interference Coordination (ICIC) using frequency reuse schemes in Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks is one of the most promising approaches to reduce the effect of interference and to... more
Inter-Cell Interference Coordination (ICIC) using frequency reuse schemes in Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks is one of the most promising approaches to reduce the effect of interference and to improve the system performance. Fractional Frequency Reuse (FFR) schemes are efficient interference mitigation techniques that have been used to improve system performance in multirelay multi-cell OFDMA cellular networks, especially for the cell edge users. The purpose of FFR design is to deploy frequency patterns (sets) in such a way that a Mobile Station (MS) user can reduce interference from adjacent cells. The Frequency Reuse Factor (FRF) of 7/3 with frequency reuse pattern (7, 3, 1) is used to improve the system performance of FRF=1 and FRF=3. This paper proposes a new frequency pattern and deploys frequency sets with Amplify and Forward (AF) fixed relays to improve the performance of the system. Simulation results show that the proposed pattern achieves significant Inter-Cell Interference (ICI) reduction when compared to other cooperative and noncooperative schemes.
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Drones are becoming increasingly significant for vast applications, such as firefighting, and rescue. While flying in challenging environments, reliable Global Navigation Satellite System (GNSS) measurements cannot be guaranteed all the... more
Drones are becoming increasingly significant for vast applications, such as firefighting, and rescue. While flying in challenging environments, reliable Global Navigation Satellite System (GNSS) measurements cannot be guaranteed all the time, and the Inertial Navigation System (INS) navigation solution will deteriorate dramatically. Although different aiding sensors, such as cameras, are proposed to reduce the effect of these drift errors, the positioning accuracy by using these techniques is still affected by some challenges, such as the lack of the observed features, inconsistent matches, illumination, and environmental conditions. This paper presents an integrated navigation system for Unmanned Aerial Vehicles (UAVs) in GNSS denied environments based on a Radar Odometry (RO) and an enhanced Visual Odometry (VO) to handle such challenges since the radar is immune against these issues. The estimated forward velocities of a vehicle from both the RO and the enhanced VO are fused with...
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The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute... more
The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute positioning measurements (e.g. GPS) are typically unavailable. Laser range finders are among the most widely used sensors that help the unmanned vehicles to localize themselves in indoor environments. Typically, automatic real-time matching of the successive scans is performed either explicitly or implicitly by any localization approach that utilizes laser range finders. Many accustomed approaches such as Iterative Closest Point (ICP), Iterative Matching Range Point (IMRP), Iterative Dual Correspondence (IDC), and Polar Scan Matching (PSM) handles the scan matching problem in an iterative fashion which significantly affects the time consumption. Furthermore, the solution convergence is not guaranteed especially in cases of sharp maneuvers or fast movement. T...
The topic of this paper is delayed- decision-feedback equalization for wireless multiuser systems consisting of an arbitrary number of porta- bles (users) and one central base station. The multi- ple users are supported by means of spread... more
The topic of this paper is delayed- decision-feedback equalization for wireless multiuser systems consisting of an arbitrary number of porta- bles (users) and one central base station. The multi- ple users are supported by means of spread spectrum multiple access (SSMA) or CDMA. We consider joint or multiuser detection of all signals. In addition to bandwidth diversity, the system may employ antenna diversity at the receiver. The focus is on the reverse link. The radio channels are considered to be fre- quency selective. A flexible detection order of the multiple received signals is achieved by placing de- lay elements after the forward lters of the decision- feedback equalizer (DFE). This delays the signals of some users longer than those of others and results in dierent performance improvements for dierent users. The special cases of parallel and successive DFE result from no delays and innite delays, respec- tively. These structures are analyzed and compared to the linear MMSE eq...
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Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions' environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments... more
Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions' environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments is addressed by simultaneous localization and mapping approach using either local or global approaches. Both approaches suffer from accumulated errors and high processing time due to the iterative nature of the scan matching method. Moreover, point-to-point scan matching is prone to outlier association processes. This paper proposes a low-cost novel method for 2D real-time scan matching based on a reference key frame (RKF). RKF is a hybrid scan matching technique comprised of feature-to-feature and point-to-point approaches. This algorithm aims at mitigating errors accumulation using the key frame technique, which is inspired from video streaming broadcast process. The algorithm depends on the iterative closest point algorithm during the lack of lin...
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Page 1. STBC-DFE SYSTEMS OVER MULTIPATH FADING CHANNELS Lin Wang Dept. ofElectrical and Computer Engineering, University ofCalgary, Calgary, Alberta, Canada, T2N ]N4 email: linwang(ucalgary.ca Feng Zhang Dept. ...
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In this paper, a new reference symbol mapping scheme is proposed to improve downlink channel estimation performance over the standard reference symbol mapping scheme defined in the 3GPP LTE standard. The proposed scheme is based on the... more
In this paper, a new reference symbol mapping scheme is proposed to improve downlink channel estimation performance over the standard reference symbol mapping scheme defined in the 3GPP LTE standard. The proposed scheme is based on the concept of guarding reference symbols (i.e., pilot symbols) with null sub-carriers. This helps mitigate the effect of inter-carrier interference (ICI) at pilot sub-carriers.
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Research Interests: Nonlinear Optics, Wireless networks, Radio over fiber, Adaptive Signal Processing, Communication System, and 11 moreWireless Network, Semiconductor Lasers, Adaptive Filter, Adaptive Filters, Second Order, FIR filters, Nonlinear Distortion, Laser Diode, Dynamic Range, Finite Impulse Response Filter, and Higher order
Page 1. 4208 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 11, NOVEMBER 2008 Performance Analysis and Multi-Stage Iterative Receiver Design for Concatenated Space-Frequency Block Coding Schemes ...
Research Interests: Distributed Computing, Monte Carlo Simulation, Fading Channel, Algorithm, Numerical Simulation, and 15 moreMaximum Likelihood, Noise reduction, Frequency, Fading, Bit Error Rate, Detectors, Demodulation, Communication Complexity, Interference Cancellation, Block Codes, Electrical And Electronic Engineering, Monte Carlo Method, Fading channels, Concatenated codes, and Iterative Method
Page 1. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. XX, NO. XX, MONTH 200X... more
Page 1. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. XX, NO. XX, MONTH 200X 1 ...
Research Interests: Engineering, Channel Coding, Numerical Analysis, Comparative Study, Fading Channel, and 15 moreAlgorithm, Parameter estimation, Numerical Simulation, Channel Estimation, Computer Simulation, Mean square error, Bit Error Rate, Accuracy, Precision, Low Latency, Estimation Method, Orthogonal Frequency Division Multiplexing, Fading channels, Low Complexity, and OFDM modulation
In this paper, we propose a low-complexily iterative multiuser receiver using groupwise maximum likelihood sequence estimation (MLSE) combined with interference cancellation for a turbo coded MC-CDMA system. It is based on grouping the... more
In this paper, we propose a low-complexily iterative multiuser receiver using groupwise maximum likelihood sequence estimation (MLSE) combined with interference cancellation for a turbo coded MC-CDMA system. It is based on grouping the active users according to their signal shenglhs and computing the log-likelihood ratios by using MLSE in each group at the j r s t iteration. For subsequent iterations, a modifed interference cancellation scheme that can benejtfrom code exfrinsic information available through decoding is used. Simulation results m e presented in a Rayleigh multipath f d i n g environmenr for a data transmission scheme. Comparisons me made with iterative receivers using maximum a posteriori (MAP) criterion and soft interference cancellation. Performance ve'y close to that ofMAP based iterative receiver is achieved by this novel scheme within a fou iterations, with much lower computational requirements. This scheme performs signif cant& well also under the near far conditions.
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This paper considers the implications of using Chirp Spread Spectrum (CSS) as an antimultipath modulation technique for the transmission of high speed (> I O MB/s) data in the indoor wireless channel. Three elements are required for a CSS... more
This paper considers the implications of using Chirp Spread Spectrum (CSS) as an antimultipath modulation technique for the transmission of high speed (> I O MB/s) data in the indoor wireless channel. Three elements are required for a CSS system to perform optimally in the multipath environment-a chirp spreader/correlator for resolution of the channel multipath, a phase-dgferential modulation scheme to co-phase the multipath components and a RAKE for recombination of the symbol energy. The advantage of CSS is that all three of these elements can be implemented with simple analog hardware. A prototype CSS system is presented along with simulated and measured performance plots in the indoor channel. Test results indicate that a CSS system using DQPSK can perform within 2 dB of gaussian DQPSK in IOm Non Line of Sight (NLOS) indoor channels with excess delay 200 ns, down to bit error rates of 10-7with single omni antennas in transmitter and receiver and no coding, at data rates of 20 MB/s and higher.
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Page 1. IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 45, NO. 2, MAY 1996 217 Effects of Antenna Height, Antenna Gain, and Pattern Downtilting for Cellular Mobile Radio Edward Benner, Member, IEEE, and Abu B. Sesay, Member, IEEE ...
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Page 1. Performance Evaluation of Non-coherent Multi-tone CDMA System Quazi M. Rahman and Abu B. Sesay Department of Electrical & Computer Engineering, University of Calgary, Calgary, AB, T2NlN4, Canada Email ...
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A method for locating mobile stations in a cellular telephone system is analyzed. This method uses hyperbolic multilateration of direct sequence radio signals that are transmitted by the mobile after it has been polled. The channel that... more
A method for locating mobile stations in a cellular telephone system is analyzed. This method uses hyperbolic multilateration of direct sequence radio signals that are transmitted by the mobile after it has been polled. The channel that would be necessary for the radiolocation signal could be created by reusing an entire 10-MHz mobile radio bandwidth. A direct-sequence locating system has
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A decorrelating decision-feedback detector is considered for multiuser detection for frequency-selective synchronous CDMA channels. This detector operates on the outputs of matched filters which are matched to the original code waveforms... more
A decorrelating decision-feedback detector is considered for multiuser detection for frequency-selective synchronous CDMA channels. This detector operates on the outputs of matched filters which are matched to the original code waveforms of the system. A maximum likelihood estimation to estimate parameters of the decorrelating decision-feedback filters is proposed and derived. The estimation method is based on inserting known training sequences into the information data by all users simultaneously. To achieve minimum mean-square-error (MMSE) in estimation, a criterion for how to select the training sequences is suggested. The estimation method requires a matrix inversion at the end of each training period. The simulation results show some degradations in system performance compared to the case where the perfect knowledge of the channel is assumed. This degradation is clearly due to errors in the channel estimation
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ABSTRACT
ABSTRACT
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Fuel Optimization Using Biologically-Inspired Computational Models. [ASME Conference Proceedings 2008, 167 (2008)]. Thamar E. Mora, Abu B. Sesay, Jörg Denzinger, H. Golshan, G. Poissant, C. Konecnik. Abstract. This paper ...
In this paper, an accurate validation method for dynamic nonlinear behavioral models of wideband RF high power amplifiers is presented. This method is an indirect validation approach which is based on memoryless predistortion technique to... more
In this paper, an accurate validation method for dynamic nonlinear behavioral models of wideband RF high power amplifiers is presented. This method is an indirect validation approach which is based on memoryless predistortion technique to remove the out-of-band spectrum regrowth caused by static memoryless nonlinearities of the power amplifiers. The effectiveness of the model validation method is demonstrated with an
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Page 1. PERFORMANCE OF MRC OVER NAKAGAMI-I~Z FADING CHANNELS WITH ARBITRARY BRANCH CORRELATION, NON-IDENTICAL AND NON-INTEGRAL FADING ORDERS Tuan A. Tran and Abu B. Sesay Dept. ...
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Page 1. Proceedings of Asia-Pacific Microwave Conference 2006 Dynamic Nonlinear Behavior Characterization for Wideband RF Transmitters Using Augmented Hammerstein Models Taijun Liu*, Slim Boumaiza, Abu B. Sesay, and Fadhel M. Ghannouchi ...
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Page 1. Capacity of PPM Ultra-Wideband Communications with Inter Pulse Interference Reza Pasand John Nielsen Abu B. Sesay Siudeni member IEEE Member IEEE Senior IEEE Dept. of Electrical and Computer Eng., University of Calgary 2500 Univ.... more
Page 1. Capacity of PPM Ultra-Wideband Communications with Inter Pulse Interference Reza Pasand John Nielsen Abu B. Sesay Siudeni member IEEE Member IEEE Senior IEEE Dept. of Electrical and Computer Eng., University of Calgary 2500 Univ. ...