Current Issue : July - September Volume : 2018 Issue Number : 3 Articles : 5 Articles
A new spreading code based on a prime code for synchronous optical code-division multiple-access networks that can be used in\nmonitoring applications has been proposed. The new code is referred to as ââ?¬Å?extended grouped new modified prime code.ââ?¬Â This\nnew code has the ability to support more terminal devices than other prime codes. In addition, it patches subsequences with ââ?¬Å?0sââ?¬Â\nleading to lower power consumption. The proposed code has an improved cross-correlation resulting in enhanced BER performance.\nThe code construction and parameters are provided. The operating performance, using incoherent on-off keying\nmodulation and incoherent pulse position modulation systems, has been analyzed. The performance of the code was compared\nwith other prime codes. The results demonstrate an improved performance, and a BER floor of 10âË?â??9 was achieved....
We investigate the system performance of a two-way amplify-and-forward (AF) energy harvesting relay network over the Rician\nfading environment. For details, the delay-limited (DL) and delay-tolerant (DT) transmission modes are proposed and investigated\nwhen both energy and information are transferred between the source node and the destination node via a relay node. In the\nfirst stage, the analytical expressions of the achievable throughput, ergodic capacity, the outage probability, and symbol error ratio\n(SER) were proposed, analyzed, and demonstrated. After that, the closed-form expressions for the system performance are studied\nin connection with all system parameters. Moreover, the analytical results are also demonstrated by Monte Carlo simulation in\ncomparison with the closed-form expressions. Finally, the research results show that the analytical and the simulation results agree\nwell with each other in all system parameters....
Obfuscation of software and data is one of the subcategories of software security. Hence, the outlines of the obfuscation problem\nand its various methods have been studied in this article. This paper proposes a hybrid of two signals and encryption obfuscation\nto hide the behaviour program and prevent reconstruction of the normal code by hackers. The usual signal method is strong\nenough for obfuscation, but its problem is the high complexity because of a lot of call and return instructions. In this study, a new\ndispatcher was added to the source code to reconstruct the original control flow graph from the hidden one to solve the problem of\nthe signal method. This dispatcher code is encrypted to preclude access by the hacker. In this paper, the potency that makes the\nobfuscation strong has been increased and the resilience that makes the obfuscation poor has been decreased. The results of\na comparison of the similarity among the ambiguous data with its original code and with available efficient methods present\na performance advantage of the proposed hybrid obfuscation algorithm....
Wi-Fi has been an amazingly successful technology. Its success may be attributed to the fact that, despite the significant advances\nmade in technology over the last decade, it has remained backward compatible. 802.11ac is the latest version of the wireless LAN\n(WLAN) standard that is currently being adopted, and it promises to deliver very high throughput (VHT), operating at the 5 GHz\nband. In this paper, we report on an implementation of 802.11ac wireless LAN for residential scenario based on the 802.11ax task\ngroup scenario document. We evaluate the 802.11ac protocol performance under different operating conditions. Key features such\nas modulation coding set (MCS), frame aggregation, and multiple-input multiple-output (MIMO) were investigated. We also\nevaluate the average throughput, delay, jitter, optimum range for goodput, and effect of station (STA) density per access point\n(AP) in a network. ns-3, an open source network simulator with features supporting 802.11ac, was used to perform the simulation.\nResults obtained indicate that very high data rates are achievable. The highest data rate, the best mean delay, and mean jitter are\npossible under combined features of 802.11ac (MIMO and A-MPDU)....
Network failures are undesirable but inevitable occurrences for most modern communication and computing networks. A good\nnetwork design must be robust enough to handle sudden failures, maintain traffic flow, and restore failed parts of the network\nwithin a permissible time frame, at the lowest cost achievable and with as little extra complexity in the network as possible.\nEmerging next-generation (xG) communication and computing networks such as fifth-generation networks, software-defined\nnetworks, and internet-of-things networks have promises of fast speeds, impressive data rates, and remarkable reliability. To\nachieve these promises, these complex and dynamic xG networks must be built with low failure possibilities, high network\nrestoration capacity, and quick failure recovery capabilities. Hence, improved network restoration models have to be developed\nand incorporated in their design. In this paper, a comprehensive study on network restoration mechanisms that are being\ndeveloped for addressing network failures in current and emerging xG networks is carried out. Open-ended problems are\nidentified, while invaluable ideas for better adaptation of network restoration to evolving xG communication and computing\nparadigms are discussed....
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