Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
LTE heterogeneous networks (HetNets) is becoming a popular topic since it\nwas first developed in 3GPP Release 10. HetNets has the advantage to assemble\nvarious cell networks and enhance users� Quality of Service (QoS) within\nthe system. However, its development is still constrained by two main issues:\n1) Load imbalance caused by different transmission powers for various tiers,\nand 2) The unbalanced transmission power may also increase unnecessary\nhandover rate. In order to solve the first issue, Cell range expansion (CRE)\ncan be applied in the system, which will benefit lower-tier cell during user association\nphase; CRE, Hysteresis Margin (HM) and Time-to-Trigger (TTT)\nwill be utilized to bound UE within lower tier network of HetNets and therefore\nsolve the second issue. On the other hand, the relationship of these parameters\nmay be complicated and even reduce QoS if they are chosen incorrectly.\nThis paper will evaluate the advantage and disadvantage of all three parameters\nand propose a Markov Chain Process (MCP) based method to find optimal\nHM, CRE and TTT values. And then, the simulation is taken and the\noptimal combination for our scenario is obtained to be 1 dB, 6 dB and 60 ms\nrespectively. First contribution of this paper is to map the HetNets handover\nprocess into MCP and all the phases of handover can be calculated and analysed\nin probability way, so that further prediction and simulation can be realised.\nSecond contribution is to establish a mathematical method to model the\nrelationship of HM, CRE and TTT in HetNets, therefore the coordination of\nthese three important parameters is achieved to obtain system optimization...
In this paper, a novel Medium Access Control (MAC) protocol for industrial\nWireless Local Area Networks (WLANs) is proposed and studied. The main\nchallenge in industry automation systems is the ultra-low network latency\nwith a target upper bound in the order of 1 ms while maintaining high network\nreliability and availability. The novelty of the proposed wireless MAC\nprotocol resides in its similar latency performance as its counterpart in wired\nindustrial LAN. First, the functional design of the MAC protocol is introduced.\nThen its performance results gained from hardware implementation\n(SystemC and VHDL) on an FPGA platform are presented. Finally, a\nreal-time communication module which achieves the ultra-low latency required\nin industrial automation is described....
Despite its low computational cost, the Gradient Based Routing (GBR) broadcast of interest messages inWireless Sensor Networks\n(WSNs) causes significant packets duplications and unnecessary packets transmissions. This results in energy wastage, traffic load\nimbalance, high network traffic, and low throughput.Thanks to the emergence of fast and powerful processors, the development\nof efficient network coding strategies is expected to enable efficient packets aggregations and reduce packets retransmissions.\nFor multiple sinks WSNs, the challenge consists of efficiently selecting a suitable network coding scheme. This article proposes\na Cooperative and Adaptive Network Coding for GBR (CoAdNC-GBR) technique which considers the network density as\ndynamically defined by the average number of neighbouring nodes, to efficiently aggregate interest messages. The aggregation is\nperformed by means of linear combinations of random coefficients of a finite Galois Field of variable size GF(2...
We analyse some of the candidates for modulations for 5G: FBMC-OQAM, GFDM-OQAM, andWCP-COQAM. Unlike most of\nthe related bibliographies, which are oriented to mobile communications, our research is focused on 5G in cognitive radio based\nindustrial wireless communications. According to the ultrareliability and low-latency requirements of industrial communications,\nwe simulate the aforementioned modulations in low-band transmissions (carrier frequencies below 6GHz and a bandwidth\nnarrower than 100MHz) through large indoor spaces and severe multipath channels that emulate industrial halls. Moreover, we\ngive detailed information aboutWCP-COQAMand how the windowing affects the protection againstmultipath effect and reduces\nspectral efficiency compared to GFDM-OQAM.We also compare the aforementioned filtered multicarrier techniques and OFDM\nin terms of robustness against multipath channels, power spectral density, and spectral efficiency. Based on these results, we aim at\nproviding an approximate idea about the suitability of 5G MCM candidates for industrial wireless communications based on CR....
The modern telecommunication system is characterized by the rapid improvement\nof information and communication technologies, such as the improvement\nin the data rate, power consumption and Quality of Service (QoS).\nBased on this development, the next generation network (NGN) is shaped.\nThe NGN is represented by a packet transport network demarcated functions\nand services. To provide transport functions in NGN, using Multi-Protocol\nLabel Switching (MPLS) technology, there are two main problems, which are\nmultipath routing and traffic distribution, which are what this paper works\nwith. Accordingly, this paper proposes a solution to these two problems using\noptimization procedures to find the shortest path Dijkstra and Bellman-Ford,\nwhich is characterized by a high-speed-oriented selection of a single shortest\npath between the source and the destination, based on several selected criteria\nrelated to the optimal use of the network resources. Solving the information\nflow distribution problems in large number of nodes network applying salesman\nprocedure or having NP-completeness, causes significant time delay,\nwhich means that the proposed solution is not suitable for real time applications.\nAccordingly, for real time applications, there is a need to move to other\nmethods based on the use of several independent shortest paths....
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