Performance Evaluation of Distributed Computer-Communication Systems

1988 ◽  
Author(s):  
Leonard Kleinrock
Keyword(s):  
Performance Evaluation ◽  
Communication Systems ◽  
Computer Communication

scholarly journals Enhancing V2X Communication Based on a New Comb-Pilot Estimation Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-14
Author(s):  
Aymen Sassi ◽  
Yassin El Hillali ◽  
Atika Revenq ◽  
Faiza Charfi ◽  
Lotfi Kamoun
Keyword(s):  
Performance Evaluation ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Performance Enhancement ◽  
Human Life ◽  
Ieee 802.11P ◽  
Vehicle To Vehicle ◽  
Pilot Symbols ◽  
Quality Of Transmission

Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems, known as V2X technologies, have increasingly attracted attention in current research on road safety and traffic ergonomics. The performance evaluation of these communication systems is an important step before their potential integration and use in real systems. V2X communications are based on the IEEE 802.11p standard also known as Wireless Access in Vehicular Environment (WAVE). V2X can affect human life; therefore a deep study related to V2X performance evaluation should be done in order to be sure about the system reliability. In this context, we have elaborated a deep study related to the effect of transmission range on V2X communications by considering the terminal mobility. First, we have evaluated the performance of the PHY layer on the IEEE 802.11p using simulation. Secondly, we have conducted real case measurements using the Arada LocoMate Transmission system. The obtained results shows the necessity to optimize the quality of transmission in V2X communications. Consequently, we propose in this paper a new comb-pilot technique to enhance the quality of Orthogonal Frequency Division Multiplexing (OFDM) transmission. Our proposal consists in two new uses of the pilot subcarrier estimation technique in order to decrease the elevated bit error rate (BER). The quality of transmission (QoT) is first evaluated relating to the pilot symbol rearranged positions. Second, we proposed to optimize the QoT by adding two supplementary pilot symbols as it can offer better channel estimation results. Based on the performance evaluation of our proposal, it is confirmed that both of rearrangement and the adding of the pilot patterns lead to performance enhancement compared to baseline model (standardized one).

Online Learning Environments

2011 ◽  
pp. 678-685 ◽  
Author(s):  
Riu Hu ◽  
Shuyan Wang
Keyword(s):  
Online Learning ◽  
Learning Environment ◽  
Learning Environments ◽  
Communication Systems ◽  
The Internet ◽  
Electronic Communications ◽  
Online Learning Environments ◽  
Computer Communication ◽  
E Learning ◽  
The Web

Online learning, which was defined as a learning environment using computer communication systems for learning delivery and interaction (Harasim, 1990), has been involved into all facets of society’s education. Online learning can be considered as a subset of the category of e-learning because it refers specifically to learning that is occurring via the Internet or Intranet. Online learning environment normally refers to learning via electronic communications, coursework, and/or information posted on the Web, and through other instructional activities by using Internet.

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