In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

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Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

The remarkable growth of wireless data traffic in recent times has driven the need to explore suitable regions in the radio spectrum to meet the projected requirements. In pursuance of this, millimeter wave communications have received considerable attention in the research fraternity. Due to the high path and penetration losses at millimeter wavelengths, antenna beamforming assumes a pivotal role in establishing and maintaining a robust communication link. Beamforming for millimeter wave communications poses a multitude of diverse challenges due to the large channel bandwidth, unique channel characteristics, and hardware constraints. In this paper, we track the evolution and advancements in antenna beamforming for millimeter wave communications in the context of the distinct requirements for indoor and outdoor communication scenarios. We expand the scope of discussion by including the developments in radio frequency system design and implementation for millimeter wave beamforming. We explore the suitability of millimeter wave beamforming methods, both, existing and proposed till midyear 2015, and identify the exciting new prospects unfolding in this domain.

Beamforming for Millimeter Wave Communications: An Inclusive Survey

In millimeter-wave communication, large antenna arrays are required to achieve high power gain by steering towards each other with narrow beams, which poses the problem to efficiently search the best beam direction in the angle domain at both Tx and Rx sides. As the exhaustive search is time consuming, hierarchical search has been widely accepted to reduce the complexity, and its performance is highly dependent on the codebook design. In this paper, we propose two basic criteria for the hierarchical codebook design, and devise an efficient hierarchical codebook by jointly exploiting sub-array and deactivation (turning-off) antenna processing techniques, where closed-form expressions are provided to generate the codebook. Performance evaluations are conducted under different system and channel models. Results show superiority of the proposed codebook over the existing alternatives.

Hierarchical Codebook Design for Beamforming Training in Millimeter-Wave Communication

Over the past decade, vision-based vehicle detection techniques for road safety improvement have gained an increasing amount of attention. Unfortunately, the techniques suffer from robustness due to huge variability in vehicle shape (particularly for motorcycles), cluttered environment, various illumination conditions, and driving behavior. In this paper, we provide a comprehensive survey in a systematic approach about the state-of-the-art on-road vision-based vehicle detection and tracking systems for collision avoidance systems (CASs). This paper is structured based on a vehicle detection processes starting from sensor selection to vehicle detection and tracking. Techniques in each process/step are reviewed and analyzed individually. Two main contributions in this paper are the following: survey on motorcycle detection techniques and the sensor comparison in terms of cost and range parameters. Finally, the survey provides an optimal choice with a low cost and reliable CAS design in vehicle industries.

Vehicle Detection Techniques for Collision Avoidance Systems: A Review

In millimeter-wave communication, large antenna arrays are required to achieve high power gain by steering toward each other with narrow beams, which poses the problem to efficiently search the best beam direction in the angle domain at both Tx and Rx sides. As the exhaustive search is time consuming, hierarchical search has been widely accepted to reduce the complexity, and its performance is highly dependent on the codebook design. In this paper, we propose two basic criteria for the hierarchical codebook design, and devise an efficient hierarchical codebook by jointly exploiting sub-array and deactivation (turning-off) antenna processing techniques, where closed-form expressions are provided to generate the codebook. Performance evaluations are conducted under different system and channel models. Results show superiority of the proposed codebook over the existing alternatives.

In this article, we suggest an efficient beam switching technique for the emerging 60GHz wireless personal area networks. Given the pre-specified beam codebooks, the beam switching process, aiming to identify the best beam-pair for data transmissions, is formulated as a global optimization problem in a two-dimension plane that is formed by the potential beam pattern index. As the analytical gradient information of the objective reward function is practically unavailable, Rosenbrock numerical algorithm is properly adopted to implement beam searching, by implicitly approaching and exploiting the gradient descent direction through the numerical pattern-search mechanic. In order to enhance search performance, furthermore, a novel initialization process is presented to provide the feasible initial solution for Rosenbrock search. Inspired by the appealing conception of small-region dividing and conquering, this pre-search algorithm can efficiently reduce the search scope and hence improve the success probability. The developed beam switching technique, i.e. an initialization process followed by Rosenbrock search, exhibits a much lower complexity than the current state-of-the-art strategies. It is demonstrated from both theoretical analysis and numerical experiments that, compared with the existing popular methods, the required protocol overhead of the new beam-training procedure can be significantly reduced, accompanying the power consumption of 60GHz devices.

On the Efficient Beam-Forming Training for 60GHz Wireless Personal Area Networks

In recent years, Wireless Body Area Network (W-BAN) is attracting more and more attentions with its various applications like the medical and CE application. And these applications present diverse quality of service (QoS) requirements, so it is necessary to design a medium access control (MAC) protocol to support differentiated services for various traffics coexisting in WBAN. Addressing this problem, in this paper, a new scheme named priority-based adaptive timeslot allocation (PTA) scheme is proposed to differentiate the QoS for the priority classified data in WBAN. Simulation is constructed to testify the efficiency of the PTA scheme compared to IEEE 802.15.4 protocol, and the results show that the PTA scheme provides the better QoS for the higher priority data, and also, performs better performance in terms of the average transmission time and energy consumption efficiency.

Priority-based adaptive timeslot allocation scheme for wireless body area network

This article puts forward a method for codebook design to support beamforming mechanism in a 60GHz millimeter-wave wireless communication environment. The codebook is designed with only phase shifting but not any amplitude adjustment to meet the low power consumption requirement. IEEE802.15.3c beam MRA (main response axis) directions are taken as the original version to make curve fitting, so that weighting vector based on uniform weighting can be obtained to generate a codebook matrix. The simulation results show that, compared with the codebook in IEEE802.15.3c, similar main lobe patterns can be obtained in the proposed codebook, while the side lobe level is lower and the antenna gain at the direction of MRA is higher. Meanwhile, the interference decreases obviously with an improved network channel capacity in the practice environment, and the codebook is also robust to the beam shifting deriving from phase errors.

Beamforming codebook design and performance evaluation for 60GHz wireless communication

Modern communication engineering has brought forward impractical requirements on powerful computation engines as well as simple implementations. Apparently, the two aspects are contradicted in most realistic applications. Because of the dispersive multipath propagation in underwater acoustic channels, traditional coherent and adaptive receivers are computationally intensive and, hence, inapplicable to the large-scale underwater sensor networks. Inspired by quantum computing and nature intelligence that are incorporated with the concept of culture evolution, in this paper, we suggest a novel quantum memetic algorithm (QMA) built with more qualified problem-solving ability. Instead of classical gene representations, the quantum bit structure is employed by chromosomes to enhance the population diversity of genetic searching. The quantum gate rotating is then explored to update chromosomes in an efficiently parallel way. As a hybridization strategy, quantum-rotation-based local search is integrated in the lifetime learning to further refine individuals' performance and accelerate their convergence toward the global optimality. As a significant real-world application, we develop a noncoherent underwater signal receiver that is based on a QMA framework. From a pattern recognition aspect, the suggested detection scheme includes two sequential phases: Features extraction and pattern classification. Finally, the highly computational optimization problem is elegantly addressed by QMA. Providing favorable robustness to various parameter configurations, QMA can considerably reinforce the search performance and improve the underwater signal detection. It is demonstrated from numerical experiments that QMA is much superior to genetic algorithm (GA) in this high-dimensional optimization. Meanwhile, QMA shows remarkable advantages in search performance, even to the current state-of-the-art quantum-inspired GA and memetic algorithm.

Quantum Memetic Evolutionary Algorithm-Based Low-Complexity Signal Detection for Underwater Acoustic Sensor Networks

Millimeter wave (mmWave) communications have been regarded as a key technology for the next generation cellular systems since the huge available bandwidth can potentially provide the rates of multiple gigabits per second. In mmWave multiple-input multiple-output (MIMO) systems, the conventional precoding is infeasible due to the hardware cost and power consumption. Therefore, hybrid precoding is considered as a promising technology to provide a compromise between hardware complexity and system performance. In this paper, we investigate the designs of the hybrid precoder and combiner in mmWave MIMO systems. We adopt the hierarchical strategy to design a hybrid precoder to maximize the spectral efficiency. In particular, we focus on the optimization of analog precoder and propose a novel iterative algorithm. Then, based on the optimal analog precoder, we compute the digital precoder to improve the spectral efficiency. For practical implementation, the proposed hybrid precoder design can be used in wideband systems with orthogonal frequency division multiplexing modulation. The simulation results and mathematical analysis show that the proposed algorithm can achieve near-optimal performance with low complexity for mmWave MIMO systems.

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Weixia Zou

Papers

On the Efficient Beam-Forming Training for 60GHz Wireless Personal Area Networks

Priority-based adaptive timeslot allocation scheme for wireless body area network

Beamforming codebook design and performance evaluation for 60GHz wireless communication

Quantum Memetic Evolutionary Algorithm-Based Low-Complexity Signal Detection for Underwater Acoustic Sensor Networks

Hybrid Precoder and Combiner Design for Single-User mmWave MIMO Systems