Energy-efficient research of a transmission mode based on user cooperation

Author(s):  
Qiang Sun ◽  
Zhanqun Dong ◽  
Yutao Zhu
2012 ◽  
Vol 11 (9) ◽  
pp. 3004-3014
Author(s):  
Sumit Paul ◽  
Md. Javed Hossain ◽  
Abul Kalam Azad

MANET is collection of mobile devices form a self-creating, self-organizing and self-administering wireless networks. Due to mobility of nodes it is not possible to establish fixed paths for message delivery through the network. Hence, congestion is happening and it is the key problem for MANET. Many routing protocols have been proposed to overcome the congestion in MANET. One of the popular routing protocol is AODV, but it depends on individual receivers to detect congestion and adjust their receiving rates.  Another common routing protocol is EERCCP, which is better than AODV but sometimes it fails when link failure happens to relay node or if relay node moves from its current group to another group then there is no other mechanism to select an alternative relay nodes i.e. lack of cooperativeness. Consequently, we proposed a routing protocol named as EECCCP, which utilizes user cooperation to reduce congestion. The proposed energy efficient and cooperative congestion control routing protocol (EECCCP), performs well better than both the AODV and EERCCP. The proposed scheme encorporates the benefits of energy efficiency and cooperativeness which in turn  reduces the congestion effectively. It also overcomes the disadvantages of existing multicast congestion control protocol. Moreover, the proposed scheme does not impose any significant changes on the queuing, scheduling or forwarding policies of existing network protocols. The simulation results have shown that our proposed protocol EECCCP has the about 95% better delivery ratio and throughput with about 85 % less delay and energy consumption when compared with the existing protocol AODV. It also has the about 65% better delivery ratio and throughput with about 60 % less delay and energy consumption when compared with the existing protocol EERCCP.


Author(s):  
N. Osakabe ◽  
J. Endo ◽  
T. Matsuda ◽  
A. Tonomura

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.


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