Carles Gomez

Overview and Evaluation of Bluetooth Low Energy: An Emerging Low-Power Wireless Technology

Bluetooth Low Energy (BLE) is an emerging low-power wireless technology developed for short-range control and monitoring applications that is expected to be incorporated into billions of devices in the next few years. This paper describes the main features of BLE, explores its potential applications, and investigates the impact of various critical parameters on its performance. BLE represents a trade-off between energy consumption, latency, piconet size, and throughput that mainly depends on parameters such as connInterval and connSlaveLatency. According to theoretical results, the lifetime of a BLE device powered by a coin cell battery ranges between 2.0 days and 14.1 years. The number of simultaneous slaves per master ranges between 2 and 5,917. The minimum latency for a master to obtain a sensor reading is 676 μs, although simulation results show that, under high bit error rate, average latency increases by up to three orders of magnitude. The paper provides experimental results that complement the theoretical and simulation findings, and indicates implementation constraints that may reduce BLE performance.

Wireless home automation networks: A survey of architectures and technologies

Wireless home automation networks comprise wireless embedded sensors and actuators that enable monitoring and control applications for home user comfort and efficient home management. This article surveys the main current and emerging solutions that are suitable for WHANs, including ZigBee, Z-Wave, INSTEON, Wavenis, and IP-based technology.

Adapting AODV for IEEE 802.15.4 mesh sensor networks: theoretical discussion and performance evaluation in a real environment

The IEEE 802.15.4 standard is expected to enable a wide variety of envisaged low-cost control and monitoring applications with relaxed throughput requirements and a strong emphasis on power conservation. A routing protocol is needed for the mesh topology approach, which must take into account the very limited features of the network. In this paper we provide a three-fold contribution. We first review and discuss the main AODV based routing protocol proposals and/or implementations suitable for the quoted environments. Next, we present NST-AODV, a new AODV implementation designed to provide benefits in terms of data delivery latency, network reliability and power consumption, specially in dynamic topology networks. Finally, we evaluate the tradeoffs and most critical features of our solution in a real IEEE 802.15.4 mesh sensor network testbed

Improving performance of a real ad-hoc network by tuning OLSR parameters

A key element for MANET performance is the routing protocol. Surprisingly, little effort has been devoted up to now to analyzing the impact of routing protocol parameter settings on MANET performance. We define and study in detail the route change latency (RCL) after link failures, a critical performance metric in a non-static ad-hoc scenario, and its dependence on routing protocol parameter settings and implementation issues using OLSR. We experiment with a set of OLSR settings in a real network environment and derive its potential effect in a generic situation, showing that end-to-end connectivity can be enhanced using different parameter settings from the default ones.

Impact of LQI-based routing metrics on the performance of a one-to-one routing protocol for IEEE 802.15.4 multihop networks

The quality of an IEEE 802.15.4 link can be estimated on the basis of the Link Quality Indication (LQI), which is a parameter offered by the IEEE 802.15.4 physical layer. The LQI has been recommended by organizations such as the ZigBee Alliance and the IETF as an input to routing metrics for IEEE 802.15.4 multihop networks. As these networks evolve, one-to-one communications gain relevance in many application areas. In this paper, we present an in-depth, experimental study on the impact of LQI-based routing metrics on the performance of a one-to-one routing protocol for IEEE 802.15.4 multihop networks. We conducted our experiments in a 60-node testbed. Experiments show the spectrum of performance results that using (or not) the LQI may yield. Results also highlight the importance of the additive or multiplicative nature of the routing metrics and its influence on performance.

Networking solutions for connecting bluetooth low energy enabled machines to the internet of things

The next wave driving the expansion of the Internet will come from the Internet of Things. Bluetooth LE is a rapidly emerging ultra-low-power radio technology expected to be incorporated in billions of IoT devices in the next few years. Consequently, it is particularly important to specify Internet connectivity solutions for Bluetooth LE. In this article we present such solutions based on the ongoing standardization work in the IETF and Bluetooth Special Interest Group. We prove the feasibility of a complete IP-based protocol stack on constrained devices and illustrate its performance, highlighting key trade-offs. In addition, we discuss gateway operation covering global IPv6 connectivity and proxy-cache functionality.

Modeling the Maximum Throughput of Bluetooth Low Energy in an Error-Prone Link

We present an analytical model for the maximum throughput of Bluetooth Low Energy (BLE), considering the presence of uncorrelated bit errors and the impact of a key BLE parameter that defines the time between the start of two consecutive connection events. The derived analysis models the generic application of master-to-slave unidirectional data transmission, which also forms an upper bound for bidirectional data transmission throughput. Simulation results show that our model accurately predicts the maximum BLE throughput for all bit error rates and BLE parameter settings evaluated.

Evaluating performance of real ad-hoc networks using AODV with hello message mechanism for maintaining local connectivity

Mobile ad-hoc network (MANET) technology is an essential piece in the path towards a ubiquitous Internet. MANET routing protocol parameter configuration should be further analyzed since it may significantly impact network performance. In this paper, we perform tests in real MANET environments using the ad-hoc on-demand distance vector (AODV) routing protocol. We study the influence of the protocol, the implementation and a set of AODV link maintenance mechanisms parameter values on network performance, suggesting that usage of different settings from those proposed by default increase reactivity after topology changes with small impact on bandwidth and power consumption in a set of scenarios

Modeling the Message Count of the Trickle Algorithm in a Steady-State, Static Wireless Sensor Network

Trickle is a transmission scheduling algorithm developed for wireless sensor networks. The Trickle algorithm determines whether (and when) a message can be transmitted. Therefore, Trickle operation is critical for performance parameters such as energy consumption and available bandwidth. This letter presents an analytical model for the message count of a static Trickle-based network under steady state conditions, as a function of a parameter called the redundancy constant and the average node degree. The model presented is validated by simulation results.

Urban Automation Networks: Current and Emerging Solutions for Sensed Data Collection and Actuation in Smart Cities

Urban Automation Networks (UANs) are being deployed worldwide in order to enable Smart City applications. Given the crucial role of UANs, as well as their diversity, it is critically important to assess their properties and trade-offs. This article introduces the requirements and challenges for UANs, characterizes the main current and emerging UAN paradigms, provides guidelines for their design and/or choice, and comparatively examines their performance in terms of a variety of parameters including coverage, power consumption, latency, standardization status and economic cost.