Enhancing Downlink QoS and Energy Efficiency through a User-Centric Stienen Cell Architecture for mmWave Networks

This paper presents an analytical framework for performance characterization of a novel Stienen cell based user-centric architecture operating in millimeter wave spectrum. In the proposed architecture, at most one remote radio head (RRH) is activated within non overlapping user equipment (UE)-centric Stienen cells (S-cells) generated within the Voronoi region around each UE. Under the presented framework, we derive analytical models for the three key performance indicators (KPIs): i) SINR distribution (used as an indicator for quality of service (QoS)), ii) area spectral efficiency (ASE), and iii) energy efficiency (EE) as a function of the three major design parameters in the proposed architecture, namely UE service probability, S-cell radius coefficient and RRH deployment density. The analysis is validated through extensive Monte Carlo simulations. The simulation results provide practical design insights into the interplay among the three design parameters, tradeoffs among the three KPIs, sensitivity of each KPI to the design parameters as well as optimal range of the design parameters. Results show that compared to current non user-centric architectures, the proposed architecture not only offers significant SINR gains, but also the flexibility to meet diverse UE specific QoS requirements and trade between EE and ASE by dynamically orchestrating the design parameters

Log-moment estimators of the Nakagami-lognormal distribution

[EN] In this paper, estimators of the Nakagami-lognormal (NL) distribution based on the method of log-moments have been derived and thoroughly analyzed. Unlike maximum likelihood (ML) estimators, the log-moment estimators of the NL distribution are obtained using straightforward equations with a unique solution. Also, their performance has been evaluated using the sample mean, confidence regions and normalized mean square error (NMSE). The NL distribution has been extensively used to model composite small-scale fading and shadowing in wireless communication channels. This distribution is of interest in scenarios where the small-scale fading and the shadowing processes cannot be easily separated such as the vehicular environment.This work has been funded in part by the Programa de Estancias de Movilidad de Profesores e Investigadores en Centros Extranjeros de Ensenanza Superior e Investigacion of the Ministerio de Educacion, Cultura y Deporte, Spain, PR2015-00151 and by the Ministerio de Economia, Industria y Competitividad of the Spanish Government under the national project TEC2017-86779-C2-2-R, through the Agencia Estatal de Investigacion (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER).Reig, J.; Brennan, C.; Rodrigo Peñarrocha, VM.; Rubio Arjona, L. (2019). Log-moment estimators of the Nakagami-lognormal distribution. EURASIP Journal on Wireless Communications and Networking. 1-10. https://doi.org/10.1186/s13638-018-1328-6S110J. M. Ho, G. L. 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Performance of two way opportunistic MAC protocol in non-saturated ad hoc networks

In this paper, performance of relay based MAC protocol for two way traffic is evaluated in non-saturated condition. In real life, non-saturation is more prevalent where nodes are mostly idle. The idea of Two Way Opportunistic-Medium Access Control (TWO-MAC) protocol is inspired from the current drive to 'go green'. TWO-MAC uses high data rate nodes to work as relays (by using network coding) for the low data rate nodes in two way communications. TWO-MAC results in higher throughput, lower delays and reduced energy consumption. This is due to the use of relay and network coding for two way transmission which lowers overall blocking time and contention due to faster transmission. Further, it lowers unnecessary overhead and overhearing which reduces the energy consumption. The contribution in this work is the throughput, energy and delay gains of using network coding at the relay in a realistic non-saturated network.Scopu

Two way opportunistic MAC protocol for Ad Hoc networks

In this paper, network coding is introduced in relay based MAC protocols for bidirectional traffic to evaluate the performance in terms of throughput and energy. The idea of proposed scheme is to use high data rate nodes to work as relays for the low data rate nodes and to achieve higher throughput and reduce the energy consumption. In addition, this scheme exploits the opportunity for two way communication which is an inherent feature of 802.11 based systems. This is achieved by using network coding at the relay. This results in 1) using relay for two way transmission which lowers overall blocking time and contention due to faster transmission, 2) reducing unnecessary overhead and overhearing to reduce the energy consumption. In this work, throughput and energy gains are quantified by using network coding.Scopu

Design of radio-acoustic sensors for leakage detection in underground water pipes

The interest in the exploitation of wireless sensor networks in dissipative media (other than the free space) is nowadays growing in importance, thanks to the identification of ever newer fields of applications. This paper introduces an efficient design methodology for an easy definition of the characteristics of mobile sensors inserted in pipes filled with fluids. The proposed procedure takes into account all the physical parameters of the systems such as: the performance range of the acoustic transducer, the acoustic and electromagnetic coupling mechanism among different media, and the electromagnetic interaction within the sensor and among the electronic and metallic components. Results obtained for the design of mobile sensor networks floating in underground water conduits confirm the adequacy of the proposed metho

Self Organization of Tilts in Relay Enhanced Networks: A Distributed Solution

Despite years of physical-layer research, the capacity enhancement potential of relays is limited by the additional spectrum required for Base Station (BS)-Relay Station (RS) links. This paper presents a novel distributed solution by exploiting a system level perspective instead. Building on a realistic system model with impromptu RS deployments, we develop an analytical framework for tilt optimization that can dynamically maximize spectral efficiency of both the BS-RS and BS-user links in an online manner. To obtain a distributed self-organizing solution, the large scale system-wide optimization problem is decomposed into local small scale subproblems by applying the design principles of self-organization in biological systems. The local subproblems are non-convex, but having a very small scale, can be solved via standard nonlinear optimization techniques such as sequential quadratic programming. The performance of the developed solution is evaluated through extensive simulations for an LTE-A type system and compared against a number of benchmarks including a centralized solution obtained via brute force, that also gives an upper bound to assess the optimality gap. Results show that the proposed solution can enhance average spectral efficiency by up to 50% compared to fixed tilting, with negligible signaling overheads. The key advantage of the proposed solution is its potential for autonomous and distributed implementation