Future generation cellular networks are expected to provide ubiquitous broadband access to a continuously growing number of mobile users. In this context, LTE systems represent an important milestone towards the so called 4G cellular networks. A key feature of LTE is the adoption of advanced Radio Resource Management procedures in order to increase the system performance up to the Shannon limit.Packet scheduling mechanisms, in particular, play a fundamental role, because they are responsible for choosing, with fine time and frequency resolutions, how to distribute radio resources among different stations, taking into account channel condition and QoS requirements. This goal should be accomplished
Abstract-In the vision of heterogeneous networks, the Quality of Service provided by classic cellular systems is improved thanks to a jointly adoption of macro and small-range cells (i.e., micro, pico, and femtocells) working in the same area. This rationale has been also assimilated by 3GPP, which now proposes its possible exploitation in the upcoming Long Term Evolution-Advanced architecture. In this context, the wireless relay technology represents an interesting solution for extending the coverage of a macrocell by means of a relay node which offers wireless connectivity to mobile users and, at the same time, is connected to the eNode-B (and hence to the backbone) through a wireless backhaul link. But, the standard does not specify any optimal resource allocation strategy for the two hop path formed by the user and the backhaul links, which is indeed very relevant to satisfy the level of QoS expected by end users. To this aim, in the present contribution, we present a novel scheduling strategy, conceived as an extension of the recently proposed TwoLevel Scheduler approach, able to effectively support real-time applications in the presence of relay nodes. Its performance has been tested in several network scenarios that involve a variable number of users hosting real-time multimedia applications and best effort flows. A comparison with respect to Proportional Fair and Logarithmic strategies has been also provided, showing that the proposed approach is able to greatly reduce the Packet Loss Ratio experienced by multimedia applications, at the expense of a slight impairment of the throughput of the best effort flows.
Abstract-In network measurement systems, packet sampling techniques are usually adopted to reduce the overall amount of data to collect and process. Being based on a subset of packets, they introduce estimation errors that have to be properly counteracted by using a fine tuning of the sampling strategy and sophisticated inversion methods. This problem has been deeply investigated in the literature with particular attention to the statistical properties of packet sampling and to the recovery of the original network measurements. Herein, we propose a novel approach to predict the energy of the sampling error in the real time estimation of traffic bitrate, based on spectral analysis in the frequency domain. We start by demonstrating that the error introduced by packet sampling can be modeled as an aliasing effect in the frequency domain. Then, we derive closed-form expressions for the Signal-to-Noise Ratio (SNR) to predict the distortion of traffic bitrate estimates over time. The accuracy of the proposed SNR metric is validated by means of real packet traces. Furthermore, a comparison with respect to an analogous SNR expression derived using classic stochastic tools is proposed, showing that the frequency domain approach grants for a higher accuracy when traffic rate measurements are carried out at fine time granularity.
We expect around 9 billions people on the Earth within 2050, 70% of them living in urban environments. By that time, we have to be ready to support a never seen request for ICT services in order to improve the efficiency of future Smart Cities, thus allowing a pacific coexistence among humans. In line with this premise, the present contribution proposes a novel service platform, based on the emerging content-centric networking paradigm. It can easily embrace all available, upcoming, and remote generation wireless techologies, while supporting, at the same time, ubiquitous and secure applications in many domains, such as: e-helthcare, intelligent transportation systems, entertainment, and many others. All details of the approach we propose, have been carefully described by means of pragmatical use-cases, thus making evident its effectivenes in future realistic urban environments.
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