An Analytical Model for Estimating the Delay in Bluetooth Communications with Serial Port Profile

Bluetooth is currently a major technology for the deployment of wireless short range communications. This paper presents an ana-lytical model to compute the delay of Bluetooth transmissions with Serial Port Profile (SPP), which is nowadays widely utilized by commercial Bluetooth-enabled devices. In particular, the pro-posed equations permit to estimate the packet delay in ideal transmission conditions (when no retransmission occurs) and also when environmental noise induces losses and consequently there exist a certain probability that a packet has to be retransmitted. The model takes into consideration the overhead and segmenta-tion introduced by the protocols involved in the transmission as well as the extra delay introduced by the retransmissions. The model has been empirically validated through the measurements of Bluetooth connections in an actual test-bed.Ministerio de Educación y Ciencia TEC2006-12211-C02-0

Modeling of the Transmission Delay in Bluetooth Piconets under Serial Port Profile

Bluetooth is a key connectivity technology for the deployment of wireless Personal Area Networks as far as it is the most popular low power communication feature incorporated in devices such as laptops or smartphones. This paper proposes an analytical model to predict the delay of the transmissions in Bluetooth piconets employing Serial Port Profile (SPP), which is massively implemented by Bluetoothenabled equipments. The characterization includes the impact of the overhead and the segmentation imposed by the different protocols involved in the transmission as well as the delay provoked by the polling process that is executed to regulate the activity of the different slaves in the piconet. The model has been empirically evaluated and tested in actual Bluetooth piconetsMinisterio de Educación y Ciencia TEC2009-13763-C02-0

Analytical Characterisation of the Performance of Bluetooth Piconets Using Serial Port Profile

Bluetooth is a key connectivity technology for the deployment of wireless Personal Area Networks as far as it is the most popular low power communication feature incorporated in devices such as laptops or smartphones. This paper proposes an analytical model to predict the delay of the transmissions in Bluetooth piconets employing Serial Port Profile (SPP), which is massively implemented by Bluetooth-enabled equipments. The characterization includes the impact of the overhead and the segmentation imposed by the different protocols involved in the transmission as well as the delay provoked by the polling process that is executed to regulate the activity of the different slaves in the piconet. The model has been empirically evaluated and tested in an actual Bluetooth piconet.Ministerio de Educación y Ciencia TEC2009-13763-C02-0

Low Power Multi-Hop Networking Analysis in Intelligent Environments

Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More precisely, the paper combines the multi-hop networking with Bluetooth technology and a quality of service (QoS) metric, the latency. Bluetooth is a radio license-free worldwide communication standard that makes low power multi-hop wireless networking available. It establishes piconets (point-to-point and point-to-multipoint links) and scatternets (multi-hop networks). As a result, many Bluetooth nodes can be interconnected to set up ambient intelligent networks. Then, this paper presents the results of the investigation on multi-hop latency with park and sniff Bluetooth low power modes conducted over the hardware test bench previously implemented. In addition, the empirical models to estimate the latency of multi-hop communications over Bluetooth Asynchronous Connectionless Links (ACL) in park and sniff mode are given. The designers of devices and networks for intelligent systems will benefit from the estimation of the latency in Bluetooth multi-hop communications that the models provide.The research described in this paper was included in AIRHEM IV project and financially supported by the Basque Government Research Program called Elkartek 2015 (code KK_2015/0000085)

Bluetooth Low PowerModes Applied to the Data Transportation Network in Home Automation Systems

Even though home automation is a well-known research and development area, recent technological improvements in different areas such as context recognition, sensing, wireless communications or embedded systems have boosted wireless smart homes. This paper focuses on some of those areas related to home automation. The paper draws attention to wireless communications issues on embedded systems. Specifically, the paper discusses the multi-hop networking together with Bluetooth technology and latency, as a quality of service (QoS) metric. Bluetooth is a worldwide standard that provides low power multi-hop networking. It is a radio license free technology and establishes point-to-point and point-to-multipoint links, known as piconets, or multi-hop networks, known as scatternets. This way, many Bluetooth nodes can be interconnected to deploy ambient intelligent networks. This paper introduces the research on multi-hop latency done with park and sniff low power modes of Bluetooth over the test platform developed. Besides, an empirical model is obtained to calculate the latency of Bluetooth multi-hop communications over asynchronous links when links in scatternets are always in sniff or the park mode. Smart home devices and networks designers would take advantage of the models and the estimation of the delay they provide in communications along Bluetooth multi-hop networks

A characterization of the performance of Bluetooth 2.x + EDR technology in noisy environments

Bluetooth (BT) is by far the most popular shortrange technology for the development of wireless personal area networks and body area networks. Nowadays, BT 2.0 and 2.1 ? EDR are the most extended and implemented versions of BT standard. This article presents an analytical model that computes the packet delay of transmissions that utilize this version of BT in noisy environments. The model, which takes into account the packet retransmissions caused by noise, is particularized to calculate the mean packet delay as a function of the signal-to-noise ratio for the different enhanced data rates provided by BT 2.0 and 2.1 specifications. Thus, the model permits evaluating the efficiency of using these enhanced rates in the presence of a certain noise level.Ministerio de Ciencia e Innovación TEC2009-13763-C02-01Ministerio de Ciencia e Innovación TEC2013-42711-

Link layer protocol performance of indoor infrared wireless communications

The increasing deployment of portable computers and mobile devices leads to an increasing demand for wireless connections. Infrared presentsseveral advantagesover radio for indoor wireless connectivity but infrared link quality is affected by ambient infrared noise and by low power transmission levels due to eye safety limitations. The Infrared Data Association (IrDA) has developed the widely used IrDA 1.x protocol standard for short range, narrow beam, point to point connections.IrDA addressedthe requirement for indoor multipoint connectivity with the development of the Advanced Infrared (AIr) protocol stack. This work analyses infrared link layer design based on IrDA proposals for addressing link layer topics and suggests implementation issues and protocol modifications that improve the operation of short range infrared connections. The performance of optical wireless links is measuredby the utilization, which can be drawn at the data link layer. A new mathematical model is developed that reaches a simple equation that calculates IrDA 1.x utilization. The model is validated by comparing its outcome with simulation results obtained using the OPNET modeler. The mathematical model is employed to study the effectiveness on utilization of physical and link layer parameters.The simple equation gives insights for the optimum control of the infrared link for maximum utilization. By differentiating the utilization equation, simple formulas are derived for optimum values of the window and frame size parameters. Analytical results indicate that significant utilization increase is observed if the optimum values are implemented, especially for high error rate links. A protocolimprovement that utilizes special Supervisory frames (S-frames) to pass transmission control is proposed to deal with delays introduced by F-timer expiration. Results indicate that employing the special S-frame highly improves utilization when optimum window and frame size values are implemented. The achieved practical utilization increase for optimum parameter implementation is confirmed by meansof simulation. AIr protocol trades speedfor range by employing Repetition Rate (RR) coding to achieve the increased transmission range required for wireless LAN connectivity. AIr employs the RTS/CTS medium reservation scheme to cope with hidden stations and CSMA/CA techniques with linear contention window (CW) adjustment for medium access. A mathematical model is developed for the AIr collision avoidance (CA) procedures and validated by comparing analysis with simulation results. The model is employed to examine the effectiveness of the CA parameters on utilization. By differentiating the utilization equation, the optimum CW size that maximises utilization as a function of the number of the transmitting stations is derived. The proposed linear CW adjustment is very effective in implementing CW values close to optimum and thus minimizing CA delays. AIr implements a Go-Back-N retransmission scheme at high or low level to cope with transmission errors. AIr optionally implements a Stop-and-Wait retransmission scheme to efficiently implement RR coding. Analytical models for the AIr retransmission schemes are developed and employed to compare protocol utilization for different link parametervalues. Finally, the effectiveness of the proposedRR coding on utilization for different retransmission schemes is explored