Device-to-device communications and small cells: enabling spectrum reuse for dense networks

Abstract

In the evolution of communication networks, there has always been a need to increase the capacity to cope with the continuous growing demand for data transmission. However, with the arrival of the Internet-of-Things and the commoditization of broadband access through smartphones, tablets, smart-watches, and all types of connecting devices, future networks must be capable of providing higher bandwidth and Quality of Experience, as wellas operating in dense networks with a massive number of simultaneous connections. This high number of connections will be very heterogeneous, spanning from highly-demanding data rate applications to low-complexity and high energy-efficient Machine-to-Machine communications. In such a dense and complex scenario, a more flexible use of spectrum resources is deemed to be the way to meet the growing requirements for data transmission. In particular, this article focuses on Device-to-Device communications and small cell deployments as emerging facilitators of such a demanding and heterogeneous scenario. The pros and cons of both complementary strategies are identified from both a technical and a business point of view, and main standardization activities are discussed. The aim of this article is to identify and describe open challenges and to inspire new areas for research that make viable the next generation of dense networks.Peer ReviewedPostprint (published version

Multi-Hop Relaying: An End-to-End Delay Analysis

“…Note that here, the condition is on the dB value of the harmonic mean, contrary to (11) in which the condition is on the harmonic mean of the dB values of the SNRs.…”

“…If the high SNR achievable rate of DF given by 1 2 log 2 (min {SNR 1 , SNR 2 }) is higher than that of the P2P scheme given by 1 2 log 2 (SNR 0 ), then DF does not necessarily provide lower latency than P2P! Note that while the superiority of DF in terms of the information-theoretic achievable rate is dictated by the bottle-neck SNR between SNR 1 and SNR 2 , i.e., the condition min {SNR 1 , SNR 2 } > SNR 0 , its superiority in terms of latency is dictated by both SNR's as seen in (11).…”

Interference MAC: Impact of improper Gaussian signaling on the rate region Pareto boundary

“…This follows since the negative impact of interference can be overcome by the positive impact of increased bandwidth if the transmission is designed properly. As an example, we can think of a primary cellular network sharing resources with another system such as a Device-toDevice (D2D) communication system, a small cell [1], or more generally a secondary cognitive radio [2]. a scenario with both D2D nodes and a small cell sharing resources with a cellular network operating in uplink phase.…”

A call admission control scheme on the uplink of D2D communications underlaying cellular networks

“…Now, dramatic increase in demand for high speed wireless data services requires next generation wireless networks to significantly improve the throughput (Laya et al, 2014;Wu, Wang, Hu, Cai, & Zhou, 2014). So, it is very important to increase network capacity so as to accommodate the increasing voice and data services.…”