By Topic

Vehicular Technology, IEEE Transactions on

Issue 9 • Date Nov. 2011

Filter Results

Displaying Results 1 - 25 of 60
  • Table of contents

    Page(s): C1 - C4
    Save to Project icon | Request Permissions | PDF file iconPDF (56 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Vehicular Technology publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (43 KB)  
    Freely Available from IEEE
  • Guest Editorial Special Section on Advanced Transportation Systems

    Page(s): 4102 - 4105
    Save to Project icon | Request Permissions | PDF file iconPDF (95 KB)  
    Freely Available from IEEE
  • Specifications and Design of a PM Electric Variable Transmission for Toyota Prius II

    Page(s): 4106 - 4114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1607 KB) |  | HTML iconHTML  

    This paper focuses on an analysis of technical requirements for the design of a permanent-magnet-type electric variable transmission (PM-EVT), which is a novel series-parallel hybrid electric vehicle (HEV) powertrain concept. Similar to the planetary gear train used in Toyota Prius II, the EVT also realizes the power-split function. However, it is implemented in an electromagnetic way rather than in a mechanical way, as is the case for Prius II with a planetary gear. In this paper, a procedure to define the technical requirements of an EVT is presented. Since Toyota Prius II is a well-known series-parallel HEV, this vehicle is chosen as a reference. The engine, battery, and other necessary components are kept as input data. A dynamic simulation was performed to take into account different driving cycles. Then, based on an analysis of the simulation results (torque, speed, and power) the technical requirements of the PM-EVT are defined. Finally, the PM-EVT machine is designed. The PM-EVT design results are presented and validated using the finite-element method (FEM). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Isolated High-Power Integrated Charger in Electrified-Vehicle Applications

    Page(s): 4115 - 4126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (754 KB) |  | HTML iconHTML  

    For electric and hybrid vehicles that use grid power to charge the battery, traction circuit components are not normally engaged during the charging time; hence, there is a possibility of using the traction circuit components in the charger circuit to have an onboard integrated charger. An isolated high-power integrated charger based on a special electrical machine with a double set of stator windings is described. Through the reconfiguration of the motor stator windings in the charging mode, a six-terminal machine is achieved. The so-called motor/generator acts as an isolated three-phase power source after synchronization with the utility grid in the charging mode. This rotary isolated power source constitutes a three-phase boost rectifier (battery charger) with full utilization of the inverter. The motor windings are reconfigured by a relay-based switching device for the charging and traction modes. This paper presents the mathematical model of the motor/generator and explains the system's functionality for the traction and charging modes. Furthermore, the charger grid synchronization and charge control are described. Finally, the simulation results are presented for a practically designed system with a traction power of 25 kW and a possible charge power of 12.5 kW. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Saturation Management of a Controlled Fuel-Cell/Ultracapacitor Hybrid Vehicle

    Page(s): 4127 - 4138
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1948 KB) |  | HTML iconHTML  

    In this paper, a new control strategy, including saturation management of hybrid fuel-cell (FC)/ultracapacitor (UC) power sources, is described. First, an analysis of hybrid architectures using an FC and UCs for automotive applications is presented. Next, the model and the control strategy are described using energetic macroscopic representation (EMR). The main improvement over classical control strategies of such systems is to take into account saturation management with a dynamic reconfiguration of the energy management strategy (EMS). It includes the regenerative breaking in high state of charge (SOC) of the UC and the supply of a full power demand in low SOC of the UC. Finally, experimental results with small-scale devices show the effectiveness of the proposed control strategy using saturation management. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Practical Control Structure and Energy Management of a Testbed Hybrid Electric Vehicle

    Page(s): 4139 - 4152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3085 KB) |  | HTML iconHTML  

    The aim of this paper is to present the practical control structure (PCS) and energy management strategy of a testbed hybrid electric vehicle (HEV). This vehicle is equipped with batteries, a supercapacitor system, and a fuel cell system (FCS). The PCS, based on the energetic macroscopic representation methodology, is used to evaluate and compare the different energy management strategies to be implemented in the vehicle. This paper introduces a dynamic strategy to manage the energy in the hybrid electric vehicle; this strategy uses a fuzzy logic controller and considers the slow dynamics in the FCS, the vehicle speed, and the state of charge in the supercapacitors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synthesis of Real-World Driving Cycles and Their Use for Estimating PHEV Energy Consumption and Charging Opportunities: Case Study for Midwest/U.S.

    Page(s): 4153 - 4163
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1560 KB) |  | HTML iconHTML  

    This paper analyzes plug-in hybrid electric vehicle (PHEV) behavior, its impact on the electric grid, and possible charging opportunities using representative synthetic cycles with the consideration of daily driving schedules. The representative naturalistic cycles are synthesized through a stochastic process utilizing transition probability matrices extracted from naturalistic driving data collected in the Midwest region of the United States. The representativeness of the cycles is achieved through the subsequent statistical analysis. The distributions of the departure/arrival time and the rest time, analyzed from the real-world data at the key locations, complete the picture to analyze vehicle daily missions and the PHEV impact on the grid. PHEV simulation is used to determine the battery state of charge (SOC) distribution upon arrival. The results for typical locations such as residential, work, large business, and small business allow the assessment of the PHEV impact on the grid and possible charging opportunities during daily missions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Energy-Source-Sizing Methodology for Hybrid Fuel Cell Vehicles Based on Statistical Description of Driving Cycles

    Page(s): 4164 - 4174
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1502 KB) |  | HTML iconHTML  

    This paper describes a new methodology based on the statistical description of driving cycles to size the energy source of a hybrid vehicle. This methodology is applied to a fuel-cell-based collection truck for very specific driving patterns. Based on experimental data, random driving cycles are then generated, allowing the distribution of the average powers and energies to be computed. The analysis proves that a 20-kW fuel cell stack is sufficient for a 13 000-kg truck. The results show that the fuel cell system could be downsized, compared with classical solutions, where much larger fuel cells are required. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimized Interference Canceling for Colocated Base Station Transceivers

    Page(s): 4175 - 4183
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (727 KB) |  | HTML iconHTML  

    Strong jamming signals from colocated transmitters can cause intermodulation and desensitization in receiver circuits. Cancellation circuits can remove interference but generate noise and distortion of their own. We analyze such a system using a signal-to-interference-and-noise ratio (SINR) measure. We show that the cancellation coupler can be optimized to maximize the SINR. The optimum coupler value is proportional to the expected level of the jammers. A hardware prototype reduced the jammers by 46 dB in a controlled experiment and by 25 dB in an over-the-air experiment. A convergence time of 8.4 ms was sufficient for this application. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Amplitude and Phase Mismatches Calibration Technique for the LINC Transmitter With Unbalanced Phase Control

    Page(s): 4184 - 4193
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1237 KB) |  | HTML iconHTML  

    The linear amplifier with nonlinear components (LINC) is highly efficient because it uses a highly efficient nonlinear power amplifier (PA). However, the linearity performance of the LINC system is easily degraded by amplitude and phase mismatches between the two paths. In this paper, we propose a novel mismatch calibration technique for the LINC system that calibrates both phase and amplitude mismatches with only phase control. The technique detects mismatches between two paths without any iteration using predefined five test vector signals. In addition, this technique corrects the path mismatches using unbalanced phase control. Therefore, the proposed scheme does not require additional amplitude mismatch control blocks such as dc/dc converters or low drop output regulators (LDO). The linearity performance of the proposed LINC system is measured with 7-MHz bandwidth orthogonal frequency-division multiplexing (OFDM) signals. According to the measurement results, the proposed technique significantly enhances linearity. The measurement results also shows that the proposed LINC system satisfies the error vector magnitude (EVM) requirement for a 16-state quadratic amplitude modulation (QAM) signal (-24 dB) and a 64-QAM signal (-31 dB) up to 3.8- and 2.35-dB amplitude mismatches, respectively, with any phase mismatch. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comparison of Open Circuit Flux Control Capability of a Series Double Excitation Machine and a Parallel Double Excitation Machine

    Page(s): 4194 - 4207
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1849 KB) |  | HTML iconHTML  

    Double excitation synchronous machines combine permanent-magnet (PM) excitation with wound field excitation. The goal behind the principle of double excitation is to combine the advantages of PM-excited machines and wound field synchronous machines. These machines can constitute an energy-efficient solution for vehicle propulsion. This paper presents a comparison of the open circuit flux control capability of two structures of double excitation synchronous machines. First, a review of the state of the art of double excitation machines is presented. Then, the structures of these two machines are presented: one is a series double excitation synchronous machine and the other is a parallel double excitation synchronous machine. Finally, the open circuit flux control capabilities of both structures are compared. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Customizable Automotive Steering System With a Haptic Feedback Control Strategy for Obstacle Avoidance Notification

    Page(s): 4208 - 4216
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    Increased global use of motorized vehicles has led to a higher number of automotive crashes involving human injuries and fatalities. Greater driver awareness through haptic feedback can provide vital information from the vehicle and surroundings to the driver while minimizing driver distraction. In this paper, steering wheel haptic feedback will be provided to increase the drivers' knowledge of the roadway and driving conditions. This increased knowledge should enable the driver to avoid obstacles presented in the roadway earlier than without any feedback. A high-fidelity customizable driving simulator was utilized to provide nine different levels of sinusoidal haptic feedback via the steering wheel. Mathematical models for the vehicle steering system, with adjustable controller gains, were developed to create torsional feedback. The testing included 25 human subjects ranging in age and driving experience. Driver preferences for feedback amplitude and frequency were gathered, whereas driver/vehicle performance was used as the measure of feedback effectiveness. The laboratory results demonstrate that haptic steering feedback improved driver performance as measured by a 62% reduction in obstacle hit rates, small reductions in peak steering wheel angle and peak vehicle yaw rate, as well as a nearly 10 m (32.8 ft) increase in reaction distance to the obstacles. The research contribution is the successful application of an advanced steering simulator with a steering control strategy to introduce supplemental haptic feedback to the driver through the steering system for roadway avoidance notification. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of a Preview Controller for Vehicle Rollover Prevention

    Page(s): 4217 - 4226
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1504 KB) |  | HTML iconHTML  

    This paper presents a method for designing a preview controller for vehicle rollover prevention. It is assumed that a driver's steering input is previewable with a Global Positioning System (GPS) and an inertial measurement unit (IMU), or with an automatic steering system for collision avoidance. Based on a linear vehicle model, a linear optimal preview controller is designed. To avoid the full-state measurement of a linear quadratic regulator (LQR), linear quadratic static output feedback (LQ SOF) control is adopted. To compare with several types of controllers such as LQR or LQ SOF with respect to rollover prevention capabilities, Bode plot analysis based on a linear vehicle model is performed. To show the effectiveness of the proposed controller, simulations are performed on a vehicle simulation package CarSim. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Current Equalization Method for Serially Connected Battery Cells Using a Single Power Converter for Each Cell

    Page(s): 4227 - 4237
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1280 KB) |  | HTML iconHTML  

    This paper presents a method to control the current of each battery cell in a serially connected battery stack according to each cell capacity. With this method, the performance of a battery stack can be increased significantly. In a second life concept, battery cells with different capacities and even battery cells with different chemistries can be connected together. Moreover, if one or more battery cells become inoperative, then the battery stack can still be used in the limp-home operation mode. The required power converter structure and the calculation of the individual cell currents are presented, and a simulation for two different power converters during discharging and charging is performed. A current equalization prototype is used to validate the simulation results and to show the performance on a real battery stack with 12 serially connected cells. Finally, the influence of the equalization currents and the capacity variance in the battery stack on the discharging energy are investigated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Energy Management Control of Microturbine-Powered Plug-In Hybrid Electric Vehicles Using the Telemetry Equivalent Consumption Minimization Strategy

    Page(s): 4238 - 4248
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1146 KB) |  | HTML iconHTML  

    This paper presents a novel approach to the solution of the energy management problem of a microturbine-powered plug-in hybrid electric vehicle (PHEV). A series hybrid midsize sedan, utilizing a microturbine and a chargeable Li-ion battery stack as its primary energy source and energy storage system, respectively, is modeled in this paper. The equivalent consumption minimization strategy (ECMS) is utilized to minimize the driving cost based on Pontryagin's minimum principle. To identify the equivalent factor (EF), a new concept called the energy ratio is defined, which is demonstrated to be closely related to the EF over all possible trips. By detecting the vehicle position with a telemetry system and measuring the battery state of charge (SOC), the EF is updated in real time and is used as an input for the computation of the ECMS. Simulation results demonstrate that the proposed ECMS exhibits driving cost and diesel consumption equivalent to that determined from numerical dynamic programming. Significantly, the proposed approach reduces the driving cost from 7.7% to 21.6%, compared with a baseline control over both urban and highway cycles. In addition, through numerical simulations, the computational cost of the proposed strategy is demonstrated to be acceptable for industrial applications. Furthermore, because this strategy uses the feedback of the battery SOC, the control performance is insensitive to the control parameter errors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • State-of-Charge Estimation and State-of-Health Prediction of a Li-Ion Degraded Battery Based on an EKF Combined With a Per-Unit System

    Page(s): 4249 - 4260
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2437 KB) |  | HTML iconHTML  

    This paper describes the application of an extended Kalman filter (EKF) combined with a per-unit (p.u.) system to the identification of suitable battery model parameters for the high-accuracy state-of-charge (SOC) estimation and state-of-health (SOH) prediction of a Li-Ion degraded battery. Variances in electrochemical characteristics among Li-Ion batteries caused by aging differences result in erroneous SOC estimation and SOH prediction when using the existing EKF algorithm. To apply the battery model parameters varied by the aging effect, based on the p.u. system, the absolute values of the parameters in the equivalent circuit model in addition to the discharging/charging voltage and current are converted into dimensionless values relative to a set of base value. The converted values are applied to dynamic and measurement models in the EKF algorithm. In particular, based on two methods such as direct current internal resistance measurement and the statistical analysis of voltage pattern, each diffusion resistance (RDiff) can be measured and used for offline and online SOC estimations, respectively. All SOC estimates are within ±5% of the values estimated by ampere-hour counting. Moreover, it is shown that RDiff is more sensitive than other model parameters under identical experimental conditions and, hence, implementable for SOH prediction. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Antishudder Gearshift Controller Design for Automatic Transmission

    Page(s): 4261 - 4275
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1712 KB) |  | HTML iconHTML  

    To enhance gearshift quality and the durability of frictional elements, an antishudder gearshift controller design for automatic transmissions is discussed, which both makes turbine speed precisely track the desired trajectory and suppresses the output shaft oscillation. Moreover, these targets are achieved by clutch pressure control only. This paper also considered the model uncertainties of the electrohydraulic control system and disturbance, which are represented by two types of friction characteristics related to temperature, as well as age-related deterioration in automatic transmission fluid and the friction material. Sliding-mode control under the frame of the backstepping technique is used to make the controller robustly adapt to various conditions. In this paper, MATLAB is utilized as the programming environment, and the powertrain system is analyzed in the control-oriented sense. Last, the simulation of 1-2 upshift is illustrated to verify the validity of the proposed controller. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fault-Tolerant Control With Active Fault Diagnosis for Four-Wheel Independently Driven Electric Ground Vehicles

    Page(s): 4276 - 4287
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1265 KB) |  | HTML iconHTML  

    This paper presents a fault-tolerant control approach for four-wheel independently driven (4WID) electric vehicles. An adaptive control-based passive fault-tolerant controller is designed to ensure vehicle system stability and to track the desired vehicle motion when an in-wheel motor/motor driver fault happens. Due to the system actuation redundancy, it is challenging to isolate the faulty wheel and to accurately estimate the control gain of the faulty in-wheel motor/motor driver for 4WID electric vehicles. An active fault diagnosis (FD) approach is thus proposed to explicitly isolate and evaluate the fault. Based on the estimated control gain of the faulty wheel, the control efforts of all the wheels are redistributed to relieve the torque demand on the faulty wheel. Simulations using a high-fidelity CarSim full-vehicle model show the effectiveness of the proposed in-wheel motor/motor driver active fault diagnosis and fault-tolerant control approaches in various driving scenarios. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mathematical Models of the System-Level Safe Operational Areas of Power Electronic Converters in Plug-In Hybrid Electric Vehicles

    Page(s): 4288 - 4298
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1394 KB) |  | HTML iconHTML  

    With the development of plug-in hybrid electric vehicles (PHEVs), power electronics plays an increasingly important role in electric power train systems. The economic and reliable design of these power electronic systems, e.g., dc/ac inverter and battery charger, will be the inward search to popularize electric vehicles. As an extension of system-level safe operational areas (SSOAs) proposed in our previous literature, this paper details the criteria and mathematical models of SSOA for a battery charger and a three-phase two-level dc/ac inverter. Operational areas were established based on the SSOA. Thermal characteristics of the semiconductor devices, operational modes, and load characteristics were enclosed to enhance the mathematical models. Experiments on a 5-kW charger and a 55-kW/380-VAC inverter validated the effectiveness of SSOA. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coded Hierarchical Modulation for Wireless Progressive Image Transmission

    Page(s): 4299 - 4313
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2678 KB) |  | HTML iconHTML  

    A robust coded scheme for progressive multimedia transmission is proposed for additive white Gaussian noise, flat Rayleigh fading channels, and frequency-selective channels using different unequal error protection methods in combination. Hierarchical modulation is coupled with a packetization/combining strategy and an efficient channel encoder consisting of a cyclic redundancy check outer coder concatenated with an inner rate-compatible punctured convolutional coder. Distortion-optimal hierarchical parameters are jointly chosen with the set of channel coding parameters on a packet-switched wireless network with fixed length packets. A lower bound for the performance improvement of the proposed system is derived and shown to give significant gains at lower packet sizes and higher transmission rates. The proposed system is also shown to outperform several existing schemes for realistic wireless channels. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Scalable Modulation for Video Transmission in Wireless Networks

    Page(s): 4314 - 4323
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB) |  | HTML iconHTML  

    In conventional wireless systems with layered architectures, the physical (PHY) layer equally treats all data streams from the upper layers and applies the same modulation and coding schemes to them. Newer systems such as Digital Video Broadcast start to introduce hierarchical modulation schemes with SuperPosition Coding (SPC) and support data streams of different priorities. However, SPC requires specialized hardware and has high complexity, which is not desirable for handheld devices. In this paper, we propose scalable modulation (s-mod) by reusing the current mainstream modulation schemes with software-based bit remapping. The performance evaluation has shown that s-mod can achieve the same and, in some cases, even better performance than SPC with much lower complexity. We further propose how to optimize the configuration of the PHY-layer s-mod and coding schemes to maximize the utility of video streaming with scalable video coding (SVC). Simulation results demonstrate substantial performance gains using s-mod and cross-layer optimization, indicating that s-mod and SVC are a good combination for video transmission in wireless networks. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-Complexity Reduced-Rank Linear Interference Suppression Based on Set-Membership Joint Iterative Optimization for DS-CDMA Systems

    Page(s): 4324 - 4337
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1452 KB) |  | HTML iconHTML  

    This paper presents and analyzes a novel low-complexity reduced-rank linear interference suppression technique for direct-sequence code-division multiple access (DS-CDMA) systems based on the set-membership joint iterative optimization of receive parameters. Set-membership filtering is applied to the design and adaptation of the dimensionality-reducing projection matrix and the reduced-rank interference suppression filter. The specification of error bounds on the projection matrix and reduced-rank filter lead to the formation of two constraint sets from which estimates of the adaptive structures are selected at each time instant. The result is a low-complexity sparsely updating reduced-rank technique that does not require eigendecomposition or subspace tracking procedures. We develop least squares and stochastic gradient-type algorithms and a low-complexity rank-selection algorithm and also devise a time-varying adaptive error bound implementation. We present a stability and mean-square-error convergence analysis of the proposed algorithms along with a study of their complexity. The proposed schemes are applied to interference suppression in the uplink of a multiuser spread-spectrum DS-CDMA system, and the results confirm the validity of the analysis and the effective operation of the schemes. Performance comparisons are given against existing reduced-rank and full-rank algorithms, which act to highlight the improvements obtained by the proposed technique and algorithms. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Net Throughput Maximization of Per-Chunk User Scheduling for MIMO-OFDM Downlink

    Page(s): 4338 - 4348
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (498 KB) |  | HTML iconHTML  

    Per-chunk user scheduling for multiple-input-multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) downlink is considered. By grouping adjacent subcarriers into chunks, the amount of required channel state information feedback is reduced. Based on the net throughput criterion, which accounts for the reduction in sum rate due to the feedback overhead, it is shown that there exists an optimal chunk size that maximizes the net throughput. To reduce the feedback requirement even further, an opportunistic feedback scheme is proposed, and a close approximation for its net throughput is derived. The net throughput of per-chunk user scheduling with optimized chunk size is compared to various other limited-feedback MIMO-OFDM downlink strategies. The results show that increasing the total number of users in the system results in the net throughput of most existing MIMO-OFDM downlink schemes decreasing to zero for moderate-size user pools, whereas the net throughput of per-chunk user scheduling with opportunistic feedback increases with the total number of users, even when that number is very large(>; 1000). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of Spectrum Sensing Reliability on the Capacity of Multiuser Uplink Cognitive Radio Systems

    Page(s): 4349 - 4362
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB) |  | HTML iconHTML  

    In this paper, we investigate the performance of opportunistic scheduling in uplink cognitive radio (CR) systems by taking into account the CR users' spectrum sensing reliability. In uplink CR systems, each secondary transmitter (CR user) has a spectrum sensing responsibility to protect the primary system, and the secondary receiver (base station) schedules the transmission opportunities for the CR users. We propose novel optimal and suboptimal scheduling schemes by simultaneously taking into account the spectrum sensing reliability and the data channel quality. Analytical performance results for the proposed suboptimal scheduling schemes show that the spectrum sensing reliability should be considered for scheduling to maximize the capacity of the secondary system. Moreover, we also analyze the achievable multiuser diversity (MUD) gain of one of the proposed suboptimal scheduling schemes, which is based on the linear combination of the sensing channel and the data channel qualities. We show that the MUD gain of uplink CR systems grows significantly slower than that of conventional multiuser systems, particularly if the quality of the sensing channel is poor. Analytical and simulation results confirm that the proposed optimal and suboptimal scheduling schemes taking into account the spectrum sensing reliability and the data channel quality yield significant performance gains compared with conventional opportunistic scheduling. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEEE Transactions on Vehicular Technology covers land, airborne, and maritime mobile services, vehicular electrotechnology, equipment, and systems identified with the automotive industry.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Yuguang Michael Fang
University of Florida