The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE) as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage.

This survey aims to encourage the multidisciplinary communities to join forces for innovation in the mobile health monitoring area. Specifically, multidisciplinary innovations in medical emergency scenarios can have a significant impact on the effectiveness and quality of the procedures and practices in the delivery of medical care. Wireless body sensor networks (WBSNs) are a promising technology capable of improving the existing practices in condition assessment and care delivery for a patient in a medical emergency. This technology can also facilitate the early interventions of a specialist physician during the pre-hospital period. WBSNs make possible these early interventions by establishing remote communication links with video/audio support and by providing medical information such as vital signs, electrocardiograms, etc. in real time. This survey focuses on relevant issues needed to understand how to setup a WBSN for medical emergencies. These issues are: monitoring vital signs and video transmission, energy efficient protocols, scheduling, optimization and energy consumption on a WBSN.

The Help4Mood EU FP7 project (H4M) [1] proposes to significantly advance the state-ofthe-art in computerized support for people with Major Depression by monitoring mood, physical activity and voice characteristics while promoting activities in reaction to examined inputs. Employing actigraphy can provide supplementary data about patients with depression. Nonetheless, its use is not standardized and there is a lack of public analyses about treated patients with depression using this technique, which is the objective of the project. The purpose of the Personal Monitoring System (PMS) used in H4M is to compile objective data about the changes and trends of activity patterns during long periods of time. This would comprise daily activity, rest time and, if possible, sleep quality. The PMS uses inconspicuous methods but keeping the cost associated with sensor installation at the patient¿s home to a minimum. This work focuses on the Wireless Sensor Network (WSN) enhancements introduced after real testbeds and considering User Quality of Experience (QoE), mainly oriented to reduce energy consumption and required data transmission and consequently improving the autonomy and range of the sensors.Peer ReviewedPostprint (published version

Timing points used in running races and other competition events are generally based on radiofrequency identification (RFID) technology. Athletes' times are calculated via passive RFID tags and reader kits. Specifically, the reader infrastructure needed is complex and requires the deployment of a mat or ramps which hide the receiver antennae under them. Moreover, with the employed tags, it is not possible to transmit additional and dynamic information such as pulse or oximetry monitoring, alarms, etc. In this proposal, we present a system based on Bluetooth Low Energy which allows complete real-time position monitoring of the users using mobile phones on the organizer side and BLE sensors on the participants' side. Along with the proposal, we present a complete architecture and an extensive analysis of metrics which are determinant for evaluating the performance of the proposed system: detection probability, range, mobility patterns of runners in real races, detection delay, packet collision, energy consumption, performance under high sensor density, etc. All these results, obtained through both experimental measurements and computer simulation, will demonstrate the viability and benefits of the system against other alternatives for the intended application.