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

Mobile Ad-Hoc Networks

Ad-hoc networks are a key in the evolution of wireless networks. Ad-hoc networks are typically composed of equal nodes, which communicate over wireless links without any central control. Ad-hoc wireless networks inherit the traditional problems of wireless and mobile communications, such as bandwidth optimisation, power control and transmission quality enhancement. In addition, the multi-hop nature and the lack of fixed infrastructure brings new research problems such as configuration advertising, discovery and maintenance, as well as ad-hoc addressing and self-routing. Many different approaches and protocols have been proposed and there are even multiple standardization efforts within the Internet Engineering Task Force, as well as academic and industrial projects. This chapter focuses on the state of the art in mobile ad-hoc networks. It highlights some of the emerging technologies, protocols, and approaches (at different layers) for realizing network services for users on the move in areas with possibly no pre-existing communications infrastructure

Throughput Performance Evaluation and Analysis of Unmodified Bluetooth Devices

The Air Force relies on the application of new technologies to support and execute its mission. As new technologies develop, the integration of that technology is studied to determine the costs and benefits it may provide to the war fighter. One such emergent technology is the Bluetooth wireless protocol, used to connect a small number of devices over a short distance. The short distance is a feature that makes using the protocol desirable. However short, there is still a vulnerability to interception. This research identifies ranges at which several commercially available Bluetooth devices are usable. Various combinations of both distance and orientation are varied to determine a 360 degree map of the Bluetooth antenna. The map identifies distances at which certain throughput thresholds are available. This research shows that baseline 1 mW Bluetooth antennas are capable of throughput levels of 100 kbps at over 40 meters, which is four times the minimum distance specified in the protocol standard. The 3Com PC card was the best performing PC card, capable of throughputs at or near 100 kbps out to 40 meters. The other PC Cards tested had similar performance. The Hawking USB dongle was the best USB antenna tested, achieving throughputs of over 200 kbps in three of the four orientation, and over 150 kbps at the fourth. The 3Com dongle was a close second, the Belkin dongle a distant third, while the DLink antenna was not able to achieve 100 kbps at any distance tested

Interference Mitigation in Wireless Communications

The primary objective of this thesis is to design advanced interference resilient schemes for asynchronous slow frequency hopping wireless personal area networks (FH-WPAN) and time division multiple access (TDMA) cellular systems in interference dominant environments. We also propose an interference-resilient power allocation method for multiple-input-multiple-output (MIMO) systems. For asynchronous FH-WPANs in the presence of frequent packet collisions, we propose a single antenna interference canceling dual decision feedback (IC-DDF) receiver based on joint maximum likelihood (ML) detection and recursive least squares (RLS) channel estimation. For the system level performance evaluation, we propose a novel geometric method that combines bit error rate (BER) and the spatial distribution of the traffic load of CCI for the computation of packet error rate (PER). We also derived the probabilities of packet collision in multiple asynchronous FH-WPANs with uniform and nonuniform traffic patterns. For the design of TDMA receivers resilient to CCI in frequency selective channels, we propose a soft output joint detection interference rejection combining delayed decision feedback sequence estimation (JD IRC-DDFSE) scheme. In the proposed scheme, IRC suppresses the CCI, while DDFSE equalizes ISI with reduced complexity. Also, the soft outputs are generated from IRC-DDFSE decision metric to improve the performance of iterative or non-iterative type soft-input outer code decoders. For the design of interference resilient power allocation scheme in MIMO systems, we investigate an adaptive power allocation method using subset antenna transmission (SAT) techniques. Motivated by the observation of capacity imbalance among the multiple parallel sub-channels, the SAT method achieves high spectral efficiency by allocating power on a selected transmit antenna subset. For 4 x 4 V-BLAST MIMO systems, the proposed scheme with SAT showed analogous results. Adaptive modulation schemes combined with the proposed method increase the capacity gains. From a feasibility viewpoint, the proposed method is a practical solution to CCI-limited MIMO systems since it does not require the channel state information (CSI) of CCI.Ph.D.Committee Chair: Professor Gordon L. StBe

Evaluating interference in Bluetooth classic and Bluetooth low energy technology

Applied project submitted to the Department of Computer Science, Ashesi University College, in partial fulfillment of Bachelor of Science degree in Computer Science, April 2017Wireless communication is one of the dominant discoveries to mankind. Bluetooth, a wireless technology, is a crucial technology enabling wireless communications and more importantly, the internet of things. A recognized challenge in Bluetooth communication is the overlap of frequencies for specific time slots causing decreased throughput and delay of signals. This is described as Bluetooth interference. In order to improve communications in the internet of things, there is the need to evaluate and improve the Bluetooth technology. In this project, Bluetooth interference is evaluated using simulation. The two technologies involved are Bluetooth Classic and Bluetooth Low Energy. Simulation results are to help make informed decisions and recommendations in the usage of Bluetooth devices in coexistence. Findings in this study, confirm the presence of interference in the two technologies, and their relationship with the number of communicating pairs. Moreover, the incidence of interference is found to be relatively high in the Bluetooth Low Energy technology.Ashesi University Colleg

Device Discovery in Frequency Hopping Wireless Ad Hoc Networks

This research develops a method for efficient discovery of wireless devices for a frequency hopping spread spectrum, synchronous, ad hoc network comprised of clustered sub-networks. The Bluetooth wireless protocol serves as the reference protocol. The development of a discovery, or outreach, method for scatternets requires the characterization of performance metrics of Bluetooth piconets, many of which are unavailable in literature. Precise analytical models characterizing the interference caused to Bluetooth network traffic by inquiring devices, the probability mass function of packet error rates between arbitrary pairs of Bluetooth networks, and Bluetooth discovery time distribution are developed. Based on the characterized performance metrics, three scatternet outreach methods are developed and compared. Outreach methods which actively inquire on a regular basis, as proposed in literature, are shown to produce lower goodput, have greater mean packet delay, require more power, and cause significant delays in discovery. By passively remaining available for outreach, each of these disadvantages is avoided

AN EFFICIENT COMBINED CONGESTION HANDLING=--A--cN-:cD~-­ ROUTE MAINTENANCE PROTOCOL FOR DYNAMIC ENVIRONMENT IN BLUETOOTH NETWORK

Bluetooth IS a widespread technology for small wireless networks that permits Bluetooth devices to construct a multi-hop network called a scatternet. A large number of connections passing through a single master/ bridge device may create the problem of congestion in a Bluetooth scatternet. In addition, routing in a multi-hop dynamic Bluetooth network, where a number of masters and bridges exist, sometimes creates technical hitches in a scatternet. It has been observed that frequent link disconnections and a new route construction consume more system resources that ultimately degrade the performance of the whole network. As, Bluetooth specification has defined piconet configuration, scatternet configuration has still not been standardized. The main objective of this thesis is to provide an efficient combined protocol for scatternet congestion handling and route maintenance. The methodology contains three parts