David Garcia-Roger

Adaptive admission control scheme for multiservice mobile cellular networks

We propose a novel adaptive scheme that operates in association with either of two admission control policies, the multiple guard channel (MGC) and the multiple fractional guard channel (MFGC) policies. We provide two different implementations of the scheme, which adapt the configuration parameters of the associated policy according to the perceived QoS. The numerical evaluation carried out shows that the QoS objective is met with an excellent precision and the convergence period is much shorter than in previous proposals (approximately in the range of a thousand seconds), confirming that our approach can satisfactorily deal with the nonstationarity of an operating network. Two other key features of our scheme are its simplicity and time independency.

Adaptive admission control in mobile cellular networks with streaming and elastic traffic

We propose a novel adaptive reservation scheme that handles, in an integrated way, streaming and elastic traffic. The scheme continuously adjusts the quality of service perceived by users, adapting to any mix of traffic and enforcing a differentiated treatment among services, both in fixed and variable capacity systems. The performance evaluation carried out verifies that the QoS objective is met with an excellent precision and that it converges rapidly to new operating conditions. Other key features of our scheme are its simplicity and its oscillation-free behavior.

Maximizing the capacity of mobile cellular networks with heterogeneous traffic

We propose a novel adaptive reservation scheme that handles, in an integrated way, heterogeneous traffic of two types: streaming and elastic. The scheme adjusts the rates of streaming sessions to meet the QoS objective, adapting to any mix of traffic and enforcing a differentiated treatment among services, in both fixed and variable capacity systems. The resource utilization achieved by streaming traffic is close to the one obtained by an optimal policy, while the efficiency in the use of resources achieved by elastic traffic is greatly improved by limiting the abandonment probability. The performance evaluation carried out verifies that the QoS objective is met with an excellent precision and that the scheme converges rapidly to new operating conditions. We also compare the new adaptive scheme with two previous ones verifying that ours performs better in terms of carried traffic and convergence rate. The proposed scheme has low complexity which makes it practical for real cellular networks.

Adaptive trunk reservation policies in multiservice mobile wireless networks

We propose a novel adaptive reservation scheme designed to operate in association with the well-known Multiple Guard Channel (MGC) admission control policy. The scheme adjusts the MGC configuration parameters by continuously tracking the Quality of Service (QoS) perceived by users, adapting to any mix of aggregated traffic and enforcing a differentiated treatment among services during underload and overload episodes. The performance evaluation study confirms that the QoS objective is met with an excellent precision and that it converges rapidly to new operating conditions. These features along with its simplicity make our scheme superior to previous proposals and justify that it can satisfactorily deal with the non-stationary nature of an operating network.

Hardware testbed for sidelink transmission of 5G waveforms without synchronization

This paper details a hardware testbed conceived for studying the impact of the lack of synchronism between transmitters on several 5G waveform candidates, which is of special relevance for car-to-car communications. The experimental results show that a proper fitting of waveforms in a software-defined platform would permit increasing the range of communication between cars without peer-to-peer synchronization, paving the way for the real development of collision avoidance messages.

On the Conditions That Justify Requiring Dynamic Reconfigurability in WDM–TDMA Optical Access Networks

In a passive optical network with a hybrid wavelength division multiplexing time division multiple-access scheme, implementing reconfigurable wavelength assignment is complex; hence the need to determine the conditions for which the capacity improvements justify requiring reconfigurability over adopting a more inexpensive fixed wavelength assignment. Fixed and reconfigurable approaches to wavelength assignment are modeled and evaluated under nonstationary traffic conditions. The performance improvement is obtained in terms of bit rate gain relative to the nominal bandwidth and depends on the number of wavelength channels as well as the magnitude of the load offered by the optical network units. In addition, frame delay and frame loss in relation to the bit rate performance are obtained for Pareto and exponentially distributed traffic. Simulations show that when introducing reconfigurability, typical peak bit rate gains with respect to the fixed case are 17%, and maxima of 175% are potentially possible when traffic demands are particularly uneven.

Optimal Design of Multiple Fractional Guard Channel Policy in Multiservice Cellular Networks

In this paper we compute the optimal configuration of the Multiple Fractional Guard Channel (MFGC) admission policy in multiservice mobile wireless networks. The optimal configuration maximizes the offered traffic that the system can handle while meeting certain QoS requirements but computing the optimal parameter setting of this policy can constitute a high computational cost. To face these computational limitations an approximation based on Kaufman & Roberts recursion is evaluated and an algorithm is proposed. Moreover, we also propose an adaptative algorithm.The numerical results show that it is not easy to find a fast and accurate algorithm, in this sense the adaptative method yields the best results.

5G Visualization: The METIS-II Project Approach

One of the main objectives of the METIS-II project was to enable 5G concepts to reach and convince a wide audience from technology experts to decision makers from non-ICT industries. To achieve this objective, it was necessary to provide easy-to-understand and insightful visualization of 5G. This paper presents the visualization platform developed in the METIS-II project as a joint work of researchers and artists, which is a 3D visualization tool that allows viewers to interact with 5G-enabled scenarios, while permitting simulation driven data to be intuitively evaluated. The platform is a game-based customizable tool that allows a rapid integration of new concepts, allows real-time interaction with remote 5G simulators, and provides a virtual reality-based immersive user experience. As a result, the METIS-II visualization platform has successfully contributed to the dissemination of 5G in different fora and its use will be continued after METIS-II.

Multicarrier Waveform Harmonization and Complexity Analysis for an Efficient 5G Air Interface Implementation

The coexistence of multiple air interface variants in the upcoming fifth generation (5G) wireless technology remains a matter of ongoing discussion. This paper focuses on the physical layer of the 5G air interface and provides a harmonization solution for the joint implementation of several multicarrier waveform candidates. Waveforms based either on cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) or on filter bank multicarrier (FBMC) are first presented through a harmonized system model. Complexity comparisons among five different waveforms are provided. Then, the complexity of a proposed configurable hardware implementation setup for waveform transmission and reception is evaluated. As a result, the harmonized transmitter and receiver exhibit 25–40% and 15–25% less complexity in floating-point operations, respectively, in comparison to two standalone implementations of the most complex waveform instances of the CP-OFDM and FBMC families. This highlights the similarities between both families and illustrates the component reuse advantages associated with the proposed harmonized solution.

Converged Optical Networks for Multimedia Distribution and Data Services in Hospitality Environments

Current hospitality networks are already lagging behind in terms of broadband adoption and high-speed online offered services, and they might not be able to cope with the increasing bandwidth demands required to distribute high-definition video traffic. We propose the use of a converged optical network adapted to the specific needs of the hospitality environment, providing a future-proof and easy to manage solution based on optical fiber wiring, together with radio-over-fiber techniques for wireless access. For short distance installations with reduced transmission losses, the use of plastic optical fiber will significantly lower the infrastructure costs. We use detailed full-system simulations to analyze the validity of such infrastructure to provide a unified, pervasive and future-proof all-optical solution. Bandwidth loads in excess of 5 Gb/s have been detected on the architecture, while being able to serve high-definition TV channels with ultra low latencies.