Current Issue : July - September Volume : 2017 Issue Number : 3 Articles : 5 Articles
In this paper, a method for approximating the probability distribution of sum of independent and identical Weibull\nrandom variables is adopted to analyze the performance of equal gain combiner (EGC) receiver over non-identical\nWeibull fading channel (WFC). Our main result is to derive a generalized expression of the probability density function\n(PDF) of the signal-to-noise ratio (SNR) at the EGC output in the case of non-identical WFC. Based on this PDF, accurate\napproximation of significant performance criteria, such as outage probability (OP), the amount of fading (AoF), and\naverage symbol/bit error probability (ASEP/ABEP), are derived. In addition, we derived the analytical expressions for\nchannel capacities under various adaptation policies such as optimal rate adaptation (ORA), optimal simultaneous\npower and rate adaptation (OPRA), channel inversion with fixed rate (CIFR), and truncated channel inversion with fixed\nrate (TCIFR). The proposed mathematical analysis is complemented by several numerical results and validated using\nMonte Carlo simulation method....
Although a jamming attack is an important problem in Wi-Fi networks, there is no effective solution to this\nproblem yet. In this paper, we propose a new approach to resolve jamming attacks in Wi-Fi networks based on\nthe concept of channel hopping. If we assume that the attacker does not jam all the channels simultaneously, then\nit might be possible to circumvent a jamming attack by changing the channel. A channel hopping mechanism is\ndesigned so that the access point (AP) and a normal user can agree on the next channel with a high probability\nwithout pre-sharing of any secret information between the AP and a user node. The proposed scheme is evaluated\nthrough experiment in a test bed....
This paper presents a hardware processor for 100 Gbps wireless data link layer. A serial Reed-Solomon decoder requires a clock\nof 12.5GHz to fulfill timings constraints of the transmission. Receiving a single Ethernet frame on a 100Gbps physical layer may\nbe faster than accessing DDR3 memory. Processing so fast streams on a state-of-the-art FPGA (field programmable gate arrays)\nrequires a dedicated approach. Thus, the paper presents lightweight RS FEC engine, frames fragmentation, aggregation, and a\nprotocol with selective fragment retransmission. The implemented FPGA demonstrator achieves nearly 120 Gbps and accepts bit\nerror rate (BER) up to 2...
Link layer network coding (LLNC) promises to provide high throughput in relay networks through combining packets\nat the relays and trading communication for computation. The emerging area of physical layer network coding (PLNC)\nexploits the electromagnetic nature of signals and eliminates the need for addition at the packet level, while making\nsignal design and coding schemes adaptable to the channel conditions. Although network coding has been\nextensively studied recently, physical layer network coding has not received the attention it deserves. Several recent\nworks introduced the pollution attack at the network layer; however, the network performance at the physical layer\nwith pollution attacks has not been evaluated before. The main challenge with the pollution attack involves\npropagation of the corrupted packets in an epidemic manner, which degrades performance of the network. As PLNC\nschemes boost up the network throughput, a thorough study evaluating this superiority to the LLNC scheme in\npresence of an intruder is necessary. The robustness of both schemes towards an attack have been studied in this\narticle....
Wireless technology is emerging as a key technology for the future networks. Wireless mesh networks (WMNs) have\nemerged as an indispensable technology for deployment of wireless services for various applications in personal,\nenterprise, and metropolitan areas. Researchers are working actively in different fields of WMNs for providing better\nservices. Routing protocols play a vital role in WMNs to provide reliable configuration and maintenance of topology\nof the network. Designing a suitable cost metric for routing protocols to provide quality links for data transmission\nis the backbone of WMNs. Many cost metrics have been proposed for WMNs and is still an active research topic as\nnew performance metrics need to be discovered due to the dynamics of this field. This paper considers the genetic\nalgorithm-based routing technique for WMN.\nWe have studied the existing cost metrics and proposed a genetic algorithm technique for routing in WMN. To\nevaluate the genetic algorithm, and to determine the relative performance of the genetic algorithm in the context\nof routing in WMN, we carry out experiments on two test systems. We have evaluated the quality of the results\nproduced by our algorithm with the traditional hop count metric results. Our results show that routing in WMN\nusing genetic algorithm produces better results as compared to traditional hop count metric results. Finally, we\ncarry out a detailed analysis of results, which help us in gaining an insight into the suitability of genetic algorithm\nfor routing in WMN....
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