Enhancing the Performance of Multi Hop Wireless Networks using Network Coding Based on Multicast Transmission on Same Cost Paths

Multi hop wireless networks face many challenges basically the limitation of bandwidth, loss of packets because of many problems in wireless medium also loss of paths because of the random and unpredictable movement of wireless nodes, which reduce the performance of these networks. Recently, Network coding has been used as promising technology that achieves the reliable transfer of data in wireless networks with high throughput. Considering the efficiency of this technology and with benefiting from both the same cost paths and the broadcasting property of wireless medium, a multi transmission mechanism for random linear network coding has been proposed in multi hop wireless networks, which depends on multicasting of coded packets on the same cost paths.

Enhancing the Quality of Service for Real Time and non-Real Time Application via Internet Network

Services that demanded by users via internet network are classified in two main kinds, Services work in real time such as video and voice in real time and use UDP protocol, and other services that work in non-real time such as web browsing (HTTP) and file transfer (FTP) which use TCP Protocol. In this research, we study and analyze algorithms that enhance the quality of service for various applications. For real time application, we use queues disciplines, which gives high priority for these services and achieves minimum delay. For non-real time application, we study congestion control algorithms, which achieve best performance for reliable transfer process with existing the congestion in the network. We used OPNET 14.5 program for simulating various services via internet network. Simulation results show achieving minimum delay for voice service, and achieving high transmission rate for FTP application with existing of packets loss in the network.

Evaluation Wireless Connection performance with respect to modulation scheme, transmitter power, effective interference and ECC threshold

Wireless communication has become more popular over the last decade. Although there are many advantages to use wireless over fixed line systems, there is a major disadvantage, which is a high transmission error rate in a temporal and permanent noisy environment. There are techniques to reduce effectiveness off transmission errors in wireless communications. We have discussed in this paper. Many methods and techniques have been implementing to deal and resist errors (by increasing transmission power, switching modulation scheme) as well as evaluation the wireless connection performance taking into account many factors.

Effect of Adaptve Modulation on the data rate in current Mobile Networks

This works aims to study the performance of the mobile system via studying the effects of adaptive modulation technique on the data rate. Fuzzy logic technique is used as a tool to analyze the data rate of the downlink connection depending on type of modulation, coverage quality and the distant between the receiver and the transmitter. For parameters were considered as input parameters for the fuzzy logic system mainly are: power of the station, quality of coverage, the type of modulation technique and the signal to interface noise ratio. One parameter is used as an output of the fuzzy system which is spectrum efficiency in bit per second per hertz. Analytical study to select the optimal data rates for different modulation techniques will be considered. Additionally, studying the input and output memberships of the data rate parameters using fuzzy logic will be explained. Keywords: Data rate, downlink, signal to noise ratio, modulation type, Fuzzy logic, spectrum efficiency.

Improving the throughput of reliable transfer in multi hop wireless networks using sliding window and fast retransmit with random linear network coding

Random Linear Network Coding (RLNC) is considered to be one of the promised solutions to achieve the reliability of transmission in multi hop wireless networks, Since it is based on correcting the loss of the packets in the medium through the continuity of transmitting coded packets from each segment until receiving acknowledgment of getting the required number of these packets for decoding. However, because of the nature of wireless medium and multi hops transfer, a loss or delay of the ACK may occur, which causes transmitting extra packets and time delay to the next segments, consequently decreasing the throughput of these networks. In this research, we propose a new transmission mechanism for reliable transfer in multi hops wireless networks through using the concepts of sliding window and fast retransmit with RLNC, for transmitting packets of consequent segments in specific continues flow and fast correcting the loss in these segments. Simulation results show that proposed mechanism decreases the time delay for transmission process and increases the transfer throughput of these networks.

زيادة وثوقية وصلة تحكم باستخدام الترميز المتكيف المتعدد السويات و استراتيجيات إعادة الإرسال

In this research, We interest to studying two methods of ways to increase the reliability of wireless communication, namely: hybrid retransmission protocols (HARQ Protocols) and adaptive coding data (Adaptive Coding), in order for the wireless communication system between two points: the first is fixed and represents the control and leadership station .The second represents a body moving and it is controlled from the command station , it performs various measurements and sent it to the command station.

Importance of Serve Efficiency in Tennis

This research aims to study the importance of serving efficiency in tennis. It is applied to nineteen labeled players, who have participated in the following international championships: 1-Masters-tennis tournament 2011 London; 2-Hamburg Tennis tournament; -3-china open tennis tournament2013 4-shanghai rolex masters 2013. Results of these tournaments have been analyzed and yielded the following results: the accuracy and efficiency of surving play a critical role in determining the result of the game, especially when levels of the two players are very close. Absence of focus and loss of accuracy in serving leads to increase in the number of double fault. That in turn leads to losing too many rounds in games and it also leads contender to win faultless rounds without any effort. When the player has too many aces in games, he will always be in attacking position. This is a conformation, which proves that the powerful efficiency of serving is confusing the contender and making him occupied with a defence position all the time.