Christophe Gruet

GREENET - An Early Stage Training Network in Enabling Technologies for Green Radio

In this paper, we describe GREENET (an early stage training network in enabling technologies for green radio), which is a new project recently funded by the European Commission under the auspices of the 2010 Marie Curie People Programme. Through the recruitment and personalized training of 17 Early Stage Researchers (ESRs), in GREENET we are committed to the development of new disruptive technologies to address all aspects of energy efficiency in wireless networks, from the user devices to the core network infrastructure, along with the ways the devices and equipment interact with one another. Novel techniques at the physical, link, and network layers to reduce the energy consumption and carbon footprint of 4G devices will be investigated, such as Spatial Modulation (SM) for Multiple-Input-Multiple-Output (MIMO) systems, Cooperative Automatic Repeat reQuest (C-ARQ) protocols, and Network Coding (NC) for lossy networks. Furthermore, cooperation and cognition paradigms will be exploited as additional assets to improve the energy efficiency of wireless networks with the challenging but indispensable constraint of optimizing the system capacity without degrading the users Quality-of-Service (QoS).

The LTE Evolution: Private Mobile Radio Networks

The current private mobile radio (PMR) networks propose rich voice and basic data services on a large cellular network using dedicated digital narrowband PMR standards such as Terrestrial Trunked Radio (TETRA), TETRA for Police (TETRAPOL), or Association of Public-Safety Communications Officials-Project 25 (APCO P25). Such standards provide user bit rates typically from 4 to 10 kb/s, which are less appropriate to address future PMR services requiring higher throughput, such as mail, secured Web services, video, and image delivery. The promising Third-Generation Partnership Project (3GPP) long-term evolution (LTE) solution is a candidate to address such a PMR revolution, considering some specific adaptations to be compliant with certain critical PMR requirements. This article provides an overview of these specific LTE adaptations and evaluates how they remain challenging from a standards perspective.

Green solutions for future LTE PMR networks

In this paper we propose different green solutions for adapting the Long Term Evolution (LTE) technology to the Professional Mobile Radio (PMR) requirements. The PMR networks, currently using second generation (2G) technologies, have to evolve to new broadband solutions in order to satisfy their target user demands. The energy consumption is one of the critical points of the broadband solution, and an important constraint for PMR services. We propose different solutions, going from Radio Frequency (RF) level up to the MAC level, for adapting the 4G LTE technology to PMR requirements, reduce the energy consumption and increase autonomy of mobile PMR terminals.

Uplink energy efficiency in LTE systems

This paper proposes a new method to model the instantaneous uplink (UL) energy efficiency (EE) of a mobile terminal when it is transmitting to a base station using the Long Term Evolution (LTE) technology. It is known that the transmitted power can vary significantly, mainly depending on the used modulation code scheme (MCS), or the path loss between the user equipment (UE) and the eNodeB (eNB), or even the number of resource blocks (RBs) used to send the data. Even though this transmitted power, also known as irradiated power, does not correspond to the final power consumption during an UL transmission, its variability has an impact on it. Unlike existing models, this paper considers the power consumed in the radio frequency chain and the power consumed by the baseband processing. The proposed model is expected to improve the accuracy of the theoretic measurements of both the power consumption and the EE of UL transmissions in LTE systems.

Battery-aware network discovery algorithm for mobile terminals within heterogeneous networks

As the wireless industry evolves towards heterogeneous networks, mobile terminals have been given the ability to handover from one network to another. The network selection process starts by a network discovery operation which involves scanning the candidate networks in order to collect the required information for handover decision. Such operation consumes a considerable amount of energy at the terminal-end and yet the mobile terminal battery is limited. In this paper we propose a battery-aware scanning mechanism in which the number of scanned networks is dependent on the battery level at the terminal-end. Simulation results show an improvement of the terminal performance in terms of energy consumption and energy efficiency compared to the conventional approach where all the networks are scanned periodically.

From DMO to D2D

Direct communications have been used for long time in PSNs. Today, due to the expectations of the transmitted traffic through the network and the popularity of proximity services, direct communications may also be present in the future generation of public cellular networks.