For wireless networks in the Internet of Things (IoT), cognitive radio (CR) is a promising way to obtain the available spectrum for objects Wide-band spectrum sensing plays an important role in building such CR networks of IoT In this paper, we propose a novel dynamic compressive wide-band spectrum sensing method based on channel energy reconstruction After a bank of wide-band random filters is employed to measure the channel energy, rather than to recover all the channel energy in the whole spectrum, only the channel energy with a changing occupancy status in consecutive time slots is recovered Furthermore, it is unnecessary to use reconstruction algorithm unless there are two or more channels changing their occupancy status Compared to the existing methods, our proposed schemes bear significant improvements in the probability of detection and reduction of probability of false alarms Simulation results also show its fast speed and robustness to noise

Dynamic Compressive Wide-Band Spectrum Sensing Based on Channel Energy Reconstruction in Cognitive Internet of Things

The performance of the future mobile communication system could greatly improve as a result of Device-to-Device (D2D) communication and Non-Orthogonal Multiple Access (NOMA). Reduction of the interference between the D2D users and cellular users is crucial in improving the overall throughput and efficiency of the D2D communication based on NOMA. This paper proposes a joint sub-channel and power allocation algorithm for D2D communication based on NOMA to maximize the uplink energy efficiency and throughput of the mobile communication system. The algorithm uses the Kuhn-Munkres (KM) technique to allocate a channel for each D2D group and formulates an optimal power allocation problem using Karush-Kuhn-Tucker (KKT) conditions. Simulations indicate that the proposed algorithm outperforms the current state-of-the-art algorithms in regards to energy efficiency and throughput under different network conditions.

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An Efficient Resource Allocation Algorithm for D2D Communications Based on NOMA

Device to device communication: A survey

To prevent economic losses, maintain social order, and protect the well-being of the populace during public safety and crisis recovery scenarios, such as man-made and natural disasters, the efficient and effective delivery of time-critical information to first responders and victims plays a key role. Nonetheless, too often, the communication infrastructures that enable time-critical information delivery become dysfunctional, due to traffic overloads or physical damage. Thus, the user-side solution [e.g., device-to-device (D2D) communications] and the network-side solution [e.g., dynamic wireless networks (DWNs)] are essential communication techniques that can enhance or restore communication for responders and victims in the harsh environment associated with public safety scenes. While D2D has been widely studied and investigated in legacy/commercial communication networks, as well as DWN, little work has been done toward adapting D2D and DWN from a public safety perspective. In this survey, we first design a layered structure, consisting of the public safety service layer, time-critical information delivery layer, and physical object layer, from which to consider the public safety system and its key components. We then extensively review research efforts on both D2D and DWN as complimentary user-side and network-side communication techniques toward effective public safety communications. Particularly, we investigate the approaches and standardization progress of D2D and DWN for public safety communications. Finally, we provide insights into challenges and potential solutions regarding D2D, DWN, security and resilience, and performance evaluation of public safety communication, as well as the integration of state-of-the-art communication and computing technologies to further improve time-critical information delivery in various public safety scenarios.

Survey of Public Safety Communications: User-Side and Network-Side Solutions and Future Directions

Device-to-device (D2D) communication produces a new dimension in the mobile environment, easing the data exchange process between physically neighboring devices. To achieve an effective utilization of available resources, reduce latency, improve data rates, and increase system capacity, D2D communication utilizes nearby communicating devices. The mobile operator’s action to collect the short-range communications for maintenance of the proximity-based services and improve the performance of networks drives the development of D2D. This paper presents an extensive review of proposed solutions aiming to enhance the security in D2D communication. The main goal of the research is to present an extensive review of the recent advances in various D2D domains such as the discovery process, mode selection schemes, interference management, power control techniques and finally the mode selection for D2D applications for 5G technologies. Additionally, we highlight the open problems and identify the challenges with regard to the D2D communication problem.

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Device-To-Device Communication in 5G Environment: Issues, Solutions, and Challenges

Device-to-Device (D2D) discovery is a key enabler of D2D communications for the direct exchange of local area traffic between proximity users (UEs) to improve spectral efficiency. The direct D2D discovery relies on the capabilities of the D2D UEs to autonomously indicate their presence to proximity D2D UEs. {Despite} its potential of reducing energy and signalling burden, the direct D2D discovery {has not drawn adequate attention}. In this paper, we propose a direct D2D discovery scheme based on the random backoff procedure, where D2D UEs randomly choose a backoff interval and retransmit a beacon. Compared with existing schemes, the performance of the proposed scheme can be significantly enhanced in terms of the discovery probability and the discovery delay. Several useful guidelines for its design are proposed based on our analysis. Finally, numerical results provide valuable insights on the performance tradeoff inherent to the proposed D2D discovery scheme.

Novel Device-to-Device Discovery Scheme based on Random Backoff in LTE-Advanced Networks

Device-to-device (D2D) discovery is a key enabler of D2D communications for the direct exchange of local area traffic between proximity users (UEs) to improve spectral efficiency. The direct D2D discovery relies on the capabilities of the D2D UEs to autonomously indicate their presence to proximity D2D UEs. Despite its potential of reducing energy and signaling burden, the direct D2D discovery has not drawn adequate attention. In this paper, we propose a direct D2D discovery scheme based on the random backoff procedure, where D2D UEs randomly choose a backoff interval and retransmit a beacon. Compared with existing schemes, the performance of the proposed scheme can be significantly enhanced in terms of the discovery probability and the discovery delay. Several useful guidelines for its design are proposed based on our analysis. Finally, numerical results provide valuable insights on the performance tradeoff inherent to the proposed D2D discovery scheme.

Novel Device-to-Device Discovery Scheme Based on Random Backoff in LTE-Advanced Networks

Autonomous Underwater Vehicle (AUV), also called autonomous underwater robot, refers to an underwater robot that can independently complete tasks such as autonomous navigation, autonomous obstacle avoidance, and autonomous operation without human intervention. In some complex and narrow detection scenarios, autonomous underwater robots need to have a small volume, a high level of autonomy, and good maneuverability. Here, we design a miniature autonomous underwater robot driven by propellers, which integrates a high-performance processor, camera module, high-precision inertial measurement unit (IMU), etc. The attitude and position information of the robot is obtained in real-time through the IMU, and the processor controls the motion state of the six propellers, achieving the motion in six degrees of freedom in space. The highly integrated design ensures the maximum length of the whole machine within 15 cm, the 3-way PID controller design ensures an efficient and stable attitude control, and the high-performance processor provides more possibilities for target tracking and recognition. The developed AUV in this study shows superior navigation performance through narrow passages.

Development of Autonomous Underwater Robot for Navigation through Narrow Passages

This paper presents a method for bandwidth extension in high-efficiency power amplifier (PA) design. With a phase shift in voltage waveform of the continuous class-F mode, real part of harmonic impedance is generated to expand the impedance design space at the expense of little lossy of performance. The simulation and measurement, conducted on a broadband PA covering 1.9-3.1 GHz based on the proposed method, show a good agreement with the theory. Measured results show that the fabricated PA has a drain efficiency of 66.5%-75% when delivering 41-42.3 dBm output power with a gain of 11-12.7 dB. Under a 20-MHz LTE signal excitation at 2.6 GHz, the PA exhibits an adjacent channel leakage ratio of -36.5 dBc at an average output power of 35 dBm without linearization.

Yuchuan Zhou

Papers

Novel Device-to-Device Discovery Scheme based on Random Backoff in LTE-Advanced Networks

Novel Device-to-Device Discovery Scheme Based on Random Backoff in LTE-Advanced Networks

Development of Autonomous Underwater Robot for Navigation through Narrow Passages

Bandwidth extension of continuous class-F power amplifier with phase-shifted voltage waveform