Author(s):  
Dileep Reddy Bolla ◽  
Jijesh J J ◽  
Mahaveer Penna ◽  
Shiva Shankar

Back Ground/ Aims:: Now-a-days in the Wireless Communications some of the spectrum bands are underutilized or unutilized; the spectrum can be utilized properly by using the Cognitive Radio Techniques using the Spectrum Sensing mechanisms. Objectives:: The prime objective of the research work carried out is to achieve the energy efficiency and to use the spectrum effectively by using the spectrum management concept and achieve better throughput, end to end delay etc., Methods:: The detection of the spectrum hole plays a vital role in the routing of Cognitive Radio Networks (CRNs). While detecting the spectrum holes and the routing, sensing is impacted by the hidden node issues and exposed node issues. The impact of sensing is improved by incorporating the Cooperative Spectrum Sensing (CSS) techniques. Along with these issues the spectrum resources changes time to time in the routing. Results:: All the issues are addressed with An Energy Efficient Spectrum aware Routing (EESR) protocol which improves the timeslot and the routing schemes. The overall network life time is improved with the aid of residual energy concepts and the overall network performance is improved. Conclusion:: The proposed protocol (EESR) is an integrated system with spectrum management and the routing is successfully established to communication in the network and further traffic load is observed to be balanced in the protocol based on the residual energy in a node and further it improves the Network Lifetime of the Overall Network and the Individual CR user, along with this the performance of the proposed protocol outperforms the conventional state of art routing protocols.


2020 ◽  
Vol 6 (2) ◽  
pp. 771-782 ◽  
Author(s):  
Ozan Ozyegen ◽  
Sanaz Mohammadjafari ◽  
Emir Kavurmacioglu ◽  
John Maidens ◽  
Ayse Basar Bener

Author(s):  
Hassine Moungla ◽  
Nora Touati ◽  
Ahmed Mehaoua

This work further investigates paradigm of radiation awareness three-dimentionnel models for WBAN network environments. The authors incorporate the effect of dynamic topology as well as the time domain and environment aspects. Even, if the impact of radiation to human health remains largely unexplored and controversial. They ask two fundamental issues, (a) deployment and (b) information routing taking into account radiation awarness. The authors first propose a multi objectives flow model which allows describing a new optimal deployment model for WBAN sensor devices with dynamic topology and the relevant possible trade-offs between coverage, connectivity, network life time while maintaining at low levels the radiation cumulated by wireless transmissions. They propose oblivious deployment heuristics that are radiation aware. The authors then combine them with dynamic spectrum management is proposed based multi-commodity flow model which allows to prevent sensor node saturation and take best action against reliability and the path loss, by imposing an equilibrium use of sensors during the routing process in order to “spread” radiation in a spatio-temporal way. Experimental results show that the proposed models and algorithms balances the energy consumption of nodes effectively, maximize the network lifetime . It will meet the enhanced WBANs requirements, including better delivery ratio, less reliable routing overhead. Their proposed radiation aware deployment and routing heuristics succeed to keep radiation levels low.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6021
Author(s):  
Jongwon Lee

It is necessary to devise innovative techniques to design new high-performance tandem solar cells to meet increasing energy needs. In this study, the theoretical efficiency of intermediate band solar cells (IBSCs) was increased by integrating them with tandem solar cells to produce intermediate band tandem solar cells (IBTSCs). The spectral splitting analysis indicated that the efficient absorption of sub-photon energies was necessary to ensure optimal performance of the IBSCs at each junction of the IBTSC. For this calculation, we assumed all absorption of sub-photon energies are unity. In addition, we applied the variation of absorptivity to the detailed balance limit of a double-junction (DJ) IBTSC. Furthermore, we included the impact of series and shunt resistances of a typical DJ IBTSC to investigate the variations in electrical parameters (short circuit current, open circuit voltage). The performance efficiency also depended on the illumination concentration due to the charge carrier transitions at each junction. We analyzed this aspect to determine the overall performance of the IBTSCs. We replaced the IBSC in the bottom junction with a single-junction solar cell to explore the potential of diverse tandem configurations. DJ IBTSCs achieved a limiting efficiency comparable to that of six-junction solar cells, despite the lower number of junctions. It was challenging for these cells to exhibit optimal performance because of the inefficient spectrum management in the bottom junction. It was concluded that full illumination concentration was required to achieve optimal performance in both junctions of the IBTSC.


2020 ◽  
Vol 196 ◽  
pp. 02002
Author(s):  
Vladimir Sivokon

Ionospheric irregularities make significant impact on the efficiency of radio-engineering system operation. Our investigations carried out on Kamchatka peninsula showed that field-aligned irregularities have particularly destructive influence on decame-ter radars. We pin some definite expectations with them to increase the efficiency ofradio-engineering systems by active impact on the ionosphere. One of the important parameters of such irregularities is their velocity characteristics. When determining irregularity velocity in the impact area, different approaches are used, for example, aspect scattering method which specifies velocity on the whole but does not allow one to determine its vertical and horizontal components, direction of its motion. We have developed an ap-proach which allows us to solve this problem. As an example, results of observations over EISCAT experiments in October 2019 are presented.


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