Machine-type communications: current status and future perspectives toward 5G systems

Machine-type communications (MTC) enables a broad range of applications from mission- critical services to massive deployment of autonomous devices. To spread these applications widely, cellular systems are considered as a potential candidate to provide connectivity for MTC devices. The ubiquitous deployment of these systems reduces network installation cost and provides mobility support. However, based on the service functions, there are key challenges that currently hinder the broad use of cellular systems for MTC. This article provides a clear mapping between the main MTC service requirements and their associated challenges. The goal is to develop a comprehensive understanding of these challenges and the potential solutions. This study presents, in part, a roadmap from the current cellular technologies toward fully MTC-capable 5G mobile systems.Peer reviewe

On the Multihop Relays with Multiple Antennas for LTE-A

In this paper we analyze cooperative communications for broadcast/multicast wireless communication systems based on the LTE-A standard. Multihop relays utilizing the same frequency bands as the base station are considered. These relays are equipped with multiples antennas (MIMO), at least the double of those employed at the base station side. The simulation results show that multihop relays achieve an improvement of power efficiency, while keeping the average coverage and the overall network throughput unchanged. This can be viewed as an energy-efficient wireless transmission technique, which contributes to the implementation of the green cell networks concept, as it allows a reduction in the carbon emission footprint