The exponential increase in capacity and data rate demands, along with the diversification of use cases and verticals that are planning to use cellular radio access networks (RANs) to provide connectivity, has prompted the development of the fifth generation (5G) of radio access technology. Traffic steering, which aims at optimum mapping of the data flows to the appropriate RAN access points (APs), is considered to be one of the key enablers for supporting diverse set of requirements ranging from 1000 times higher capacity than 2010 figures to 99.999 % reliability. Furthermore, to constrain power consumption due to the ultra-densification of the network in 5G, enhanced mechanisms are required that can exploit multi-connectivity. In this paper, we build upon the envisioned connectivity provided through multiple radio links and provide schemes to enable dynamic traffic steering and energy-efficient RAN moderation in 5G. First, we present the various protocol options for tight integration of long-term evolution (LTE) and 5G networks. We then investigate how faster traffic steering over the multiple radio links can be enabled, which can both reduce the packet delivery time by increasing the capacity and reliability, and also reduce the power consumption of the network through efficient operation. Detailed performance evaluations done on the various presented mechanisms indicate the technology potential of the proposed enhancements.

This document analyses the energy efficiency of two possible schemes that have been discussed as a possible way to deploy a relay enhanced network. In the first part the main results obtained in a previous work [1] are summarized, showing the energy efficiency of a relay enhanced network obtained considering small scale simulations, in a full load scenario and measuring only the radiated power. These results provided a first indication of the potentiality of relay nodes as a tool to reduce energy consumption. In the second part a deeper analysis is provided, showing how the energy efficiency of the network can be obtained also considering the whole power consumed by all the components of the transmitting nodes, and considering scenarios where the network is not fully loaded. This kind of result has been used as input to the E3F framework proposed by the EARTH project, that allows to take into account long-term traffic variations and the mix of deployments that are typical of a modern telecommunication network, providing in that way a global assessment of energy efficiency in relay enhanced network.

This document analyses the energy efficiency of two relaying schemes that represent a possible way to deploy a relay enhanced network: the two hop scheme and the multicast cooperative scheme. Results exist in literature that provide a model for the theoretical evaluation of the capacity improvement that these solutions can yield, however no analysis is available at present on the energy efficiency of these schemes. This work enhances the existing theoretical models for capacity evaluations, providing a first analysis from an energy efficiency point of view of these two approaches, considering a fully loaded network and the total emitted RF power of the transmitting nodes. Results are provided in terms of the Energy Consumption Index (ECI) of these schemes, a metric proposed in the EARTH project for the assessment of the energy consumption of network solutions. The ECI distribution is obtained and compared with the case of a network deployed without relay nodes, showing that besides the possible improvements in capacity, relays are also candidates as a valuable tool to reduce the energy consumption of a telecommunication network.

There has been a great interest in the development of high-altitude platforms, which are low cost stratospheric aircraft carrying payloads tailored for a wide range of applications in telecommunications and remote sensing. These platforms are capable of flying at altitudes ranging between 17 and 30 km, with a potential endurance of weeks to months, features that make them attractive for the provision of future personal communication services. This paper deals with the theoretical derivation of a channel model for the communication link between the platform and terrestrial mobile users or stations. In particular, we address the problem of modeling the small-scale fading effects. It is shown that the particular geometry of the propagation scenario leads to a specific model applicable to the stratospheric channel.

In recent years great interest has arisen in the development of high altitude platforms (HAP), which are low cost stratospheric aircraft carrying payloads tailored for a wide range of applications within telecommunications and remote sensing. These platforms are able to fly at altitudes ranging between 17 and 20 km, with a potential endurance of weeks to months, features that make them attractive for the provision of future personal communication services. This paper deals with the theoretical derivation of a channel model for the communication link between the platform and terrestrial mobile users or stations. Small scale fading effects are analyzed and due to the particular geometry of the propagation scenario, a specific model for the stratospheric channel is obtained.