AbstractThis paper examines the process of sending an image over wireless mobile Channels with errors while maintaining bandwidth, transmission speed and image quality. With the tremendous development in networks, new wireless channels have been opened that threaten the security of data transmitted through networks and communication channels, and from this emerged Encryption techniques to increase the security of the transmitted data, and since the digital image compression algorithm is a process to reassemble the parts of the image so that it takes less space, but this increases the impact of the error extension in sending compressed digital images and greatly reduces the quality of the received image. This prompts us in this paper to study the performance of HQAM technology for the purpose of transmitting image data over wireless communication channels containing errors. In this paper, image quality performance has been evaluated by the BER, SNR, PSNR, SSIM, and Correlation evaluation criteria. The simulated results show that there is an improvement in the image quality received using the proposed technique.
wael saleh mohamed abughres, , , Ashrf Alzrouk Almagdob1, Ahmed B. Abdurrhman, Ibrahim A.Nasir, (9-2020)

Free space optical (FSO) communication is a promising solution to deliver the last mile communication and to guarantee a high data rate. However, the performance of FSO links can be significantly degraded by adverse weather conditions. Recently, machine learning algorithms (MLAs) have emerged for robust prediction to optimize the network performance. In this work, the Quality factor (Q) of FSO systems is estimated by means of four MLA models, namely, multi-linear regression, support vector regression, decision tree regression, and random forest regression. The synthetic data is used for training and testing these MLAs models, and several atmosphere conditions are considered with multiple transceivers FSO link system. The results of decision tree and random forest models demonstrated high coefficient of determination (R 2 ) and low mean square error (MSE) as compared to the other models.
Amal A. Algedir, Taissir Y. Elganimi(10-2020)

Abstract Ad-hoc networking is a concept in computer communications, which means that users wanting to communicate with each other form a temporary network, without any form of centralized administration. Each node participating in the network acts both as host and a router and must therefore be willing to forward packets for other nodes.In a multi-hop wireless packet network, a packet traverses more than one wireless link in traveling from its source to its destination. Such wireless networks have received considerable attention recently in the context of ad hoc networks. Ad-Hoc networks are self-organizing multi-hop wireless networks where not all links along the path of a packet can be activated simultaneously. Hence the performance of a higher level mechanism, such as congestion window or Transport Layer protocol (TCP) will depend crucially on how the links are scheduled for transmission. In multiple access networks, such as the IEEE802.11 wireless LAN, the scheduling of transmissions is done by the medium access control (MAC) protocol. This transmission scheduling is completely unaware of the needs of the TCP congestion window protocol. This thesis is concerned with the poor interaction between the TCP adaptive window protocol, the IEEE 802.11 MAC protocol, and the IEEE 802.11 Ad-Hoc routing protocol. Our thesis follow on the work done by the researchers K. Nahm and C. Kuo in the paper entitled “TCP over 802.11 Multihop networks issues and Performance Enhancement” [1]. Our contributions are two-fold. First we have repeated and confirmed the simulation results reported by K.Nahm and C.Kuo using NS-2 network simulator. Second we have introduced a simple modification in the 802.11 DSR routing protocol which reduces the unnecessary VI reroutings triggered by MAC packet collisions and enforces the TCP to enter the fast retransmit / fast recovery phase to quickly recover the packet loses. This modification has been simulated using NS-2 network simulator and from the results we have found that it provides a substantial improvement in TCP performance in the situations that we have considered in the simulation models
يحي الشارف المبروك (2009)