رافد صبار عباس /

Probability density function of the sum and maximum of non-identical fluctuating two-ray variates are derived in terms of the power and exponential functions. Novel mathematically tractable expressions of the outage probability and average bit error probability for both the maximal ratio combining.

In this paper, the impact of the non-linearity of the propagation medium on the extended η - μ fading distribution is studied. In particular, the extended α - η - μ fading model in which the parameter α represents the non-linearity of the propagation environment is presented via providing the exact and asymptotic of the statistical properties, namely, the probability density function (PDF), cumulative distribution function (CDF), and generalized-moment generating function (G-MGF). To this effect, exact closed-form mathematically tractable expressions of the outage probability (OP), average symbol error probability (ASEP), amount of fading (AoF), channel quality estimation index (CQEI) and effective rate (ER) are obtained. The asymptotic behaviour at high average signal-to-noise (SNR) values is also analysed to gain further insights into the influence of the index α on the performance metrics of the wireless communication systems. Moreover, the average channel capacity (ACC) under different adaptive transmission techniques, such as, optimum rate and adaptation (ORA), capacity of the channel with inversion and fixed rate (CIFR), and truncated inversion and fixed rate (TIFR) are derived. The validation of the derived expressions is verified via comparing the numerical results with the Monte-Carlo simulations as well as some previous works for different scenarios.

This paper introduces a smart data packet routing protocol (SMART) based on swarm technology for mobile ad hoc networks. The main challenge facing a routing protocol is to cope with the dynamic environment of mobile ad hoc networks. The problem of finding best route between communication end points in such networks is an NP problem. Swarm algorithm is one of the methods used solve such a problem. However, copping with the dynamic environment will demand the use of a lot of training iterations. We present a new infrastructure where data packets are smart enough to guide themselves through best available route in the network. This approach uses distributed swarm learning approach which will minimize convergence time by using smart data packets. This will decrease the number of control packets in the network as well as it provides continues learning which in turn provides better reaction to changes in the network environment. The learning information is distributed throughout the nodes of the network. This information can be used and updated by successive packets in order to maintain and find better routes. This protocol is a hybrid Ant Colony Optimization (ACO) and river formation dynamics (RFD) swarm algorithms protocol. ACO is used to set up multi-path routes to destination at the initialization, while RFD mainly used as a base algorithm for the routing protocol. RFD offers many advantages toward implementing this approach. The main two reasons of using RFD are the small amount of information that required to be added to the packets (12 bytes in our approach) and the main idea of the RFD algorithm which is based on one kind of agent called drop that moves from source to destination only. This will eliminate the need of feedback packets to update the network and offers a suitable solution to change data packet into smart packets. Simulation results shows improvement in the throughput and reduction in end to end delay and jitter compared to AODV and AntHocNet protocols.

A theory to allocate a wavelength in the tree networks coordinated arrangement in m -arity networks is proposed. Wavelength required equations to support all-to-all unicasting in the network according to its depth are presented. Three cases are examined: when nodes are only targets, sources or target and source in the same time. The trade-off between wavelength cost and wavelength conversion cost is considered; therefore, concentration is on wavelength allocation without conversion.

A distributed wavelength assignment technology has been investigated in this work. The Distributed Static Highest Number of Destination (DSHND) algorithm is analysed and compared with two other distributed algorithms. The tree network investigated in this work is a binary tree instead of random trees assumed in other works. The main purpose of the proposed algorithm is to increase network capacity, minimize number of converters and reduce conversion range between the input and output wavelength

In recent years, Wireless Mesh Networks (WMNs) considered as a practical solution for last-mile broadband wireless internet access. In this mode of wireless ad hoc networks, nodes may play the role of APs or Mesh Routers (MRs) to offer a short way to packets to find their destinations. However, as each node in WMNs has to transmit extra relayed traffic as well as its own; the capacity of such networks is limited by traffic congestion. To alleviate such a problem, Cognitive Radio (CR) technology can be used in which mesh nodes are allowed to use the available frequency bands that are not utilized by any licensed user. However, using this technology will impose several challenges influence the performance of the network. Interference between simultaneous transmissions, fading and environmental noise are the most important challenges that have been discussed widely in the research field. In this paper, we present a cooperative sensing scheme with interference mitigation for WMNs. In particular, we investigate the impact of false-alarm and missed-detection probabilities on the MAC layer performance. We propose a sensing strategy in which the MRs (unlicensed users) can use the available licensed spectrum without causing harmful interference with the licensed users. The simulation results have shown that the proposed scheme can improve the throughput of CR mesh networks.

بحث علمي في مجال هندسة الإتصالات قد تم نشره بواسطة فريق بحثي أحد أعضاءه تدريسي في قسم الهندسة الكهربائية في كلية الهندسة - جامعة الكوفة تحت عنوان "Simple PDF of the sum and maximum of non-identical fluctuating two-ray variates"

لقد تم إختيار الدكتور رافد صبار الأستاذ في جامعة الكوفة كلية الهندسة كمقيم للبحوث العلمية في المؤسسة العلمية البريطانية IET وقد تم تقييم عشرة بحوث خلال العامين 2018-2019 وهم كما موضح أدناه: 1. 'A Dynamic Heuristics for the Recomposition of Service Function Chain' 2. 'Energy Efficient Channel Quality based Receiver Initiated Routing Protocol for WSNs' 3. Design and Implementation of a Small AODF 4. Modeling and Analysis of Handover and Cell Association Strategy in Downlink Heterogeneous Cellular Network 5. 'Improving Performance of Neurons by Adding Color Noise' 6. VINE: Load-Balancing Clos-Network Switch with Virtual Input-Module Output Queues at Central Stage 7. Investigation of blind CFO Estimation for GFDM System using USRP: Theory, Simulations, and Experiments 8. Cog-SDN: Mitigation Mechanism for TCP-SYN Flooding Attacks in Software Defined Networks 9. 'Resource Management for Inband D2D Communication in Dense mmWave 5G Cellular Networks' 10. Load-Balanced Birkhoff-von Neumann with Greedy Scheduling Multicast Switch