Author(s):  
Xiuhua Fu ◽  
Tian Ding ◽  
Rongqun Peng ◽  
Cong Liu ◽  
Mohamed Cheriet

AbstractThis paper studies the communication problem between UAVs and cellular base stations in a 5G IoT scenario where multiple UAVs work together. We are dedicated to the uplink channel modeling and the performance analysis of the uplink transmission. In the channel model, we consider the impact of 3D distance and multi-UAVs reflection on wireless signal propagation. The 3D distance is used to calculate the path loss, which can better reflect the actual path loss. The power control factor is used to adjust the UAV's uplink transmit power to compensate for different propagation path losses, so as to achieve precise power control. This paper proposes a binary exponential power control algorithm suitable for 5G networked UAV transmitters and presents the entire power control process including the open-loop phase and the closed-loop phase. The effects of power control factors on coverage probability, spectrum efficiency and energy efficiency under different 3D distances are simulated and analyzed. The results show that the optimal power control factor can be found from the point of view of energy efficiency.


2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Myeong-Eun Hwang ◽  
Sungoh Kwon

We propose two master-slave flip-flops (FFs) that utilize the clocked CMOS (C2MOS) technique with an internal direct connection along the main signal propagation path between the master and slave latches and adopt an adaptive body bias technique to improve circuit robustness.C2MOSstructure improves the setup margin and robustness while providing full compatibility with the standard cell characterization flow. Further, the direct path shortens the logic depth and thus speeds up signal propagation, which can be optimized for less power and smaller area. Measurements from test circuits fabricated in 130 nm technology show that the proposed FF operates down to 60 mV, consuming 24.7 pW while improving the propagation delay, dynamic power, and leakage by 22%, 9%, and 13%, respectively, compared with conventional FFs at the iso-output-load condition. The proposed FFs are integrated into an8×8FIR filter which successfully operates all the way down to 85 mV.


2013 ◽  
Vol 385-386 ◽  
pp. 1527-1530 ◽  
Author(s):  
Jie Chen ◽  
Dong Ya Shen ◽  
Na Yao ◽  
Ren Zhang

Walfisch - Bertoni model is used to predict the average signal field intensity of the main street. The model considers the path loss of the free space, diffraction loss along the path, and the influence of the height of the building. There are six City parameters in Walfisch - Bertoni model influence communication quality. In this paper, the researches about path loss and its characteristics is under the case of considering two city parameters at the same time. Facts have proved that this case is more close to the actual that the wireless signal propagation environment. This paper mainly researched the path loss, probability density function (PDF) and cumulative distribution function (CDF) of the path loss.


Author(s):  
MirHojjat Seyedi ◽  
Zibo Cai ◽  
Daniel T. H. Lai

Intrabody communication (IBC) is one of the recent physical layers of the IEEE 802.15.6 Wireless Body Area Networks (WBAN) communication standard. It is employed for data transmission in low frequency bands (21 MHz as per standard, 0.3-120 MHz in literature), providing up to 10 Mbps data throughput. An effective way to increase data rate communication is to determine higher operation frequency bands. This paper reports empirical studies which explore signal propagation through the human body including limb joints within the 0.3-200 MHz frequency range. Results show that minimum signal attenuation points occur at 50 MHz and 150 MHz within the range of investigation. The presence of the joint segments along the signal propagation path causes on average 2.0 dB loss (at 50 MHz and 150 MHz), 6.0 dB loss (<1 MHz) and less than 3.0 dB (>150 MHz) compared to limb segments.


1993 ◽  
Vol 5 (1) ◽  
pp. 107-113 ◽  
Author(s):  
A. E. Reznikov ◽  
A. I. Sukhorukov ◽  
D. E. Edemskii ◽  
V. V. Kopeikin ◽  
P. A. Morozov ◽  
...  

The paper discusses ELF-VLF investigations of the low Antarctic ionosphere. Two new methods of lower ionospheric diagnostics are based on an investigation of the VLF electromagnetic field structure in the Earth-ionosphere cavity. One method deals with the analysis of local transverse cavity resonances in the near field of an emitter (a horizontal antenna) with a frequency (~1.5-8 kHz) in the range of the first few resonances. The other method, based on tweek investigations, is applicable under night conditions and enables the characteristics of the low ionosphere to be determined over a signal propagation path. The use of the ELF-VLF transmitter at Siple Station provides a unique opportunity to implement these methods, as does the ELF multipoint recording in the Schumann resonance band of atmospherics excited by powerful lightning discharges.


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