Constant monitoring of patients without disturbing their daily activities can be achieved through mobile networks. Sensor nodes distributed in a home environment to provide home assistance gives concept of Wireless We...
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ISBN:
(纸本)9781467321648
Constant monitoring of patients without disturbing their daily activities can be achieved through mobile networks. Sensor nodes distributed in a home environment to provide home assistance gives concept of Wireless Wearable Body Area networks. Gathering useful information and its transmission to the required destination may face several problems. In this paper we figure out different issues and discuss their possible solutions in order to obtain an optimized infrastructure for the care of elderly people. Different channel models along withtheir characteristics, noise filtering in different equalization techniques, energy consumption and effect of different impairments have been discussed in our paper. the novelty of this work is that we highlighted multiple issues along withtheir possible solutions that a BAN infrastructure is still facing.
the report analyses the current development tendencies of integrated telecommunications systems, factors to limit this development, and provides some new approaches to upgrade the cellular network. Advantages of the i...
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ISBN:
(纸本)9781467322287
the report analyses the current development tendencies of integrated telecommunications systems, factors to limit this development, and provides some new approaches to upgrade the cellular network. Advantages of the integrated system of cellular communication and system of differential satellite navigation - GPS (GLONASS), which is maintained in Moscow, are discussed.
this paper analyzes the robustness of the king networks for fault tolerance. To this aim, a performance evaluation of two well known fault tolerant routing algorithms in king as well as 2d networks is done. Immunet th...
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this paper analyzes the robustness of the king networks for fault tolerance. To this aim, a performance evaluation of two well known fault tolerant routing algorithms in king as well as 2d networks is done. Immunet that uses two virtual channels and Immucube, that has a better performance while requiring three virtual channels. Experimental results confirm the excellent behavior, both in performance and scalability, of the king topologies in the presence of failures. Finally, taking advantage of the topological features of king networks, a new fault tolerance routing algorithm for these networks is presented. From a cost/performance point of view this algorithm is a compromise between the two previous algorithms.
TCP Retransmission Timeouts (RTOs) related to non-congestion have been reported as one of the main reasons of the performance degradation of TCP in multi-hop wireless networks. In this paper, we introduce an efficient...
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TCP Retransmission Timeouts (RTOs) related to non-congestion have been reported as one of the main reasons of the performance degradation of TCP in multi-hop wireless networks. In this paper, we introduce an efficient algorithm called TCP NRT (Non-congestion Retransmission Timeouts) which is capable of recovering packets by detecting, differentiating and reacting to congestion as well as non-congestion RTOs. TCP NRT is able to reduce the unnecessary reduction of congestion window size and needless retransmissions. We implemented the algorithm in Qualnet network simulator and compared its performance to existing TCP versions such as Eifel, F-RTO, DSACK and EQRTO. the results from experiments show that our algorithm achieves significant performance improvement in multi-hop wireless networks.
Achieving quality of service (QoS) in IEEE 802.16 networks depends, among other factors, on mechanisms for traffic policing at the base station (BS) and subscriber stations (SSs). Since IEEE 802.16 does not include a ...
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Achieving quality of service (QoS) in IEEE 802.16 networks depends, among other factors, on mechanisms for traffic policing at the base station (BS) and subscriber stations (SSs). Since IEEE 802.16 does not include a mandatory policing, this paper proposes a policing mechanism for the SS in the uplink traffic which uses the leaky bucket mechanism (token bucket). the performance evaluation studies based on modeling and simulation have shown that the proposed mechanism is able to ensure satisfactory levels of QoS to applications, meeting their average limited delay requirements, minimum sustainable throughput and limited packet drop rate.
SpiNNaker is a custom-made architecture designed to model large-scale spiking neural nets. One of the most significant characteristics of neural nets is their extreme communication needs; each neuron propagates its ac...
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SpiNNaker is a custom-made architecture designed to model large-scale spiking neural nets. One of the most significant characteristics of neural nets is their extreme communication needs; each neuron propagates its activation to thousands of other neurons. this paper shows analytical proof that the novel multicast router in SpiNNaker is a better solution for simulating neural nets than more powerful point-to-point routers such as those found on datacentres or high performance computing systems, even when it has significantly lower requirements in terms of complexity, area and power. First, we characterised the utilization of resources required by both multicast and unicast networks. then we derived the band-width needs of different communication architectures. Finally, we derived the amount of neurons the different networks can support. From these analyses we determined that the multicast communications adopted in SpiNNaker will be able to support the target application under the expected operation conditions.
Summary form only given. Orthogonal Frequency Division Multiplexing (OFDM) is the modulation technique that is used in almost all radio and wired broadband communicationsystems. It is used in applications ranging fro...
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Summary form only given. Orthogonal Frequency Division Multiplexing (OFDM) is the modulation technique that is used in almost all radio and wired broadband communicationsystems. It is used in applications ranging from digital television, to ADSL, to powerline communications. Despite this widespread use, it has only been considered for application in optical systems in the last few years, but since then there has been an explosion of interest. Many papers have been published showing that OFDM can be applied in optical communications systems including optical wireless, long haul optical fiber, PON and plastic optical fiber. this tutorial will provide an introduction to OFDM tailored to an audience coming from an optical (rather than a radio) background. It will include an overview of recent optical OFDM research with an emphasis on optical wireless applications.
Coherent detection has boosted the applicability of digital signal processing (DSP) in optical fibre communicationsystems. Based on an universal physical structure, the digital coherent receiver is compatible with a ...
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Coherent detection has boosted the applicability of digital signal processing (DSP) in optical fibre communicationsystems. Based on an universal physical structure, the digital coherent receiver is compatible with a wide range of modulation formats and propagation scenarios. the key for this flexibility lies on an extensive usage of receiver-side DSP. In this paper we will briefly review the basic principles of the digital coherent receiver, highlighting the role of the DSP subsystem. Special emphasis will be given to the mitigation of nonlinear fibre impairments using advanced digital equalizers.
To evaluate and further develop communication protocols for transportation systems, new mobility models are required. Especially models covering the needs and specialities of trains and other track-bounded mass transp...
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ISBN:
(纸本)9781467322287
To evaluate and further develop communication protocols for transportation systems, new mobility models are required. Especially models covering the needs and specialities of trains and other track-bounded mass transportation systems are not easily available. these models play a critical role in the evaluation of hybrid and other overlay networks in which routing and handover depend on the preferences and QoS requirements of the mobile device. Here velocity and mobility play an important role, e.g. fast moving devices should not be handed over to very small cells, if possible. In this paper we present a mobility model for high-speed trains. this model is used in combination with other mobility models for cars and pedestrians to evaluate the accuracy and usefulness of different localization methods. thereafter a special localization method for high-speed trains is proposed. this is used to evaluate the quality of a location-based hybrid handover protocol.
this work presents a novel parallel multiobjective approach based on the Artificial Bee Colony algorithm for grooming low-speed traffic requests onto high-capacity optical channels. the traffic grooming problem in mes...
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this work presents a novel parallel multiobjective approach based on the Artificial Bee Colony algorithm for grooming low-speed traffic requests onto high-capacity optical channels. the traffic grooming problem in mesh optical networks is an NP-hard problem, so the usage of metaheuristics and parallelism jointly for increasing the network performance is a great option in order to reduce execution times. the parallel multiobjective approach is implemented by using OpenMP. We have measured the speedup and efficiency obtained by our parallel approach with 2, 4, 8, and 16 cores. Efficient numerical results are reported in the experimental phase conducted on two optical networks. Finally, we present a comparative study with traditional methods; in which we show that the usage of swarm intelligence outperforms previous results published in the literature.
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