Interoperability Optimization and Service Enhancement in Vehicle Onboard Infortainment Systems

This paper presents an overview on optimizing interoperability between different applications for enhanced return-on-investment through utilization of business intelligence in conjunction with prognostics and health management methodology. Such implementation is particularly suitable for deployment in mass-produced vehicle onboard diagnostics system

Development of personal area network (PAN) for mobile robot using bluetooth transceiver

The work presents the concept of providing a Personal Area Network (PAN) for microcontroller based mobile robots using Bluetooth transceiver. With the concept of replacing cable, low cost, low power consumption and communication range between 10m to 100m, Bluetooth is suitable for communication between mobile robots since most mobile robots are powered by batteries and have high mobility. The network aimed to support real-time control of up to two mobile robots from a master mobile robot through communication using Bluetooth transceiver. If a fast network radio link is implemented, a whole new world of possibilities is opened in the research of robotics control and Artificial Intelligence (AI) research works, sending real time image and information. Robots could communicate through obstacles or even through walls. Bluetooth Ad Hoc topology provides a simple communication between devices in close by forming PAN. A system contained of both hardware and software is designed to enable the robots to form a PAN and communicating, sharing information. Three microcontroller based mobile robots are built for this research work. Bluetooth Protocol Stack and mobile robot control architecture is implemented on a single microcontroller chip. The PAN enabled a few mobile robots to communicate with each other to complete a given task. The wireless communication between mobile robots is reliable based from the result of experiments carried out. Thus this is a platform for multi mobile robots system and Ad Hoc networking system. Results from experiments show that microcontroller based mobile robots can easily form a Bluetooth PAN and communicate with each other

Improving usability in pan gateways by means of a novel Bluetooth pairing method

This thesis investigates the usability issues surrounding an implementation of the Personal Area Network (PAN) Gateway, a new concept in mobile communications. The PAN Gateway device consists of a GSM/GPRS modem and a Bluetooth modem. The Bluetooth modem is used to link mobile devices to form a PAN and the GSM/GPRS modem is used to link the PAN to external networks. The possible Man Machine Interfaces for the PAN Gateway are discussed together with the usability of existing Bluetooth devices. A weakness was discovered in the usability and security of Bluetooth Pairing in existing mobile devices and this led to the development of the "Touch and Find" system and the Pairing Link Protocol. The "Touch and Find" system interacts with the Bluetooth stack and allows simple, intuitive pairing of Bluetooth devices via a serial link. A full duplex serial link was implemented using simple electrical contacts to provide the link. Inductive coupling and infrared solutions were also developed. The Pairing Link Protocol specifies the signal flow for the "Touch and Find" process. The "Touch and Find" system that was implemented using simple electrical contacts shows how simple Bluetooth pairing can be. Pairing is simply carried out by briefly touching together the devices to be paired. The "Touch and Find" system was implemented in C on Borland C++ and used in conjunction with TTPCom's Bluetooth development system, which consists of a "Mad Cow" evaluation board and Genie - a Bluetooth development tool. The research carried out demonstrates the feasibility of the "Touch and Find" system over a variety of physical mediums. The system greatly improves the usability of Bluetooth Pairing, thus improving the "Out of Box" experience. It is likely that the Inductive solution can be extended to enable battery charging across the "Touch and Find" Inductive interface, further enhancing the "value added" capabilities of this system

24GHz CMOS direct downconversion receiver front-end and VCO design

Because of advancements in RF CMOS circuits, devices, and passive elements in the last decade, it has become possible to develop a RF system-on-chip (SoC) that integrates RF, analog and digital circuits completely. Direct downconversion, or zero-IF downconversion architecture, shows an advantage over traditional superheterodyne architectures, because it eliminates the image rejection filter and IF filter, and employs only one local oscillator (LO), which reduces the receiver size and power dissipation significantly. For this reason, direct downconversion has drawn more and more attention recently in various wireless applications. However, it also presents some design challenges like flicker noise, DC offsets, even-order distortion, and I/Q mismatches. In this work, a thorough noise analysis and a comprehensive study of the noise mechanism of the low noise amplifier of CMOS direct downconversion receivers (DCR) is given. Also addressed is the design of a cross-coupled LC voltage-controlled oscillator (VCO). For the low noise amplifier, which presents major noise contribution to the DCR front-end, an optimization technique which employs both a parallel capacitance and an inter-stage inductor is proposed. The addition of this capacitance helps keep the active device relatively small, and the analysis on the effects of the inter-stage inductor shows that it helps boost gain of the LNA at the desired operation frequency of 2.4GHz, and offers a lower noise figure. In order to achieve direct downconversion, both a passive switching mixer and an active double-balanced mixer are presented. The passive switching mixer helps solve the problem of flicker noise, but suffers power loss, while the double-balanced architecture helps relieve the problems of DC offset and second-order distortion. The last part of this presentation is about a partially tunable CMOS LC-VCO which achieves good phase noise performance at the cost of smaller tuning range. It uses on-chip spiral inductors and junction varactors in the resonant LC-tank. The presented building blocks can be used for a low-power, low-voltage DCR front-end for 802.11b/g applications. It is concluded that direct downconversion architecture can find its use in low-power, low-cost 802.11b and Bluetooth applications should the circuit design make use of the optimization techniques addressed in this work

Realizing mobile multimedia systems over emerging fourth-generation wireless technologies

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (p. [161]-167) and index.by Pei-Jeng Kuo.M.Eng

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

Performance modelling and enhancement of wireless communication protocols

In recent years, Wireless Local Area Networks(WLANs) play a key role in the data communications and networking areas, having witnessed significant research and development. WLANs are extremely popular being almost everywhere including business,office and home deployments.In order to deal with the modem Wireless connectivity needs,the Institute of Electrical and Electronics Engineers(IEEE) has developed the 802.11 standard family utilizing mainly radio transmission techniques, whereas the Infrared Data Association (IrDA) addressed the requirement for multipoint connectivity with the development of the Advanced Infrared(Alr) protocol stack. This work studies the collision avoidance procedures of the IEEE 802.11 Distributed Coordination Function (DCF) protocol and suggests certain protocol enhancements aiming at maximising performance. A new, elegant and accurate analysis based on Markov chain modelling is developed for the idealistic assumption of unlimited packet retransmissions as well as for the case of finite packet retry limits. Simple equations are derived for the through put efficiency, the average packet delay, the probability of a packet being discarded when it reaches the maximum retransmission limit, the average time to drop such a packet and the packet inter-arrival time for both basic access and RTS/CTS medium access schemes.The accuracy of the mathematical model is validated by comparing analytical with OPNET simulation results. An extensive and detailed study is carried out on the influence of performance of physical layer, data rate, packet payload size and several backoff parameters for both medium access mechanisms. The previous mathematical model is extended to take into account transmission errors that can occur either independently with fixed Bit Error Rate(BER) or in bursts. The dependency of the protocol performance on BER and other factors related to independent and burst transmission errors is explored. Furthermore, a simple-implement appropriate tuning of the back off algorithm for maximizing IEEE 802-11 protocol performance is proposed depending on the specific communication requirements. The effectiveness of the RTS/CTS scheme in reducing collision duration at high data rates is studied and an all-purpose expression for the optimal use of the RTS/CTS reservation scheme is derived. Moreover, an easy-to-implement backoff algorithm that significantly enhances performance is introduced and an alternative derivation is developed based on elementary conditional probability arguments rather than bi-dimensional Markov chains. Finally, an additional performance improvement scheme is proposed by employing packet bursting in order to reduce overhead costs such as contention time and RTS/CTSex changes. Fairness is explored in short-time and long-time scales for both the legacy DCF and packet bursting cases. AIr protocol 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 1-dimensional Markov chain model is constructed instead of the bi-dimensional model in order to obtain simple mathematical equations of the average packet delay.This new approach greatly simplifies previous analyses and can be applied to any CSMA/CA protocol.The derived mathematical model is validated by comparing analytical with simulation results and an extensive Alr packet delay evaluation is carried out by taking into account all the factors and parameters that affect protocol performance. Finally, suitable values for both backoff and protocol parameters are proposed that reduce average packet delay and, thus, maximize performance

A Quantitative Analysis of Performance in a Multi-Protocol Ad Hoc 802.11b-based Wireless Local Network

The popularity of the Internet and the growing demand for ubiquitous connectivity accelerate the need for viable wireless local area network (WLAN) solutions. As a consequence, increasing number of manufacturers have adopted the Institute of Electrical and Electronic Engineers (IEEE) 802.11a/b/g set of WLAN standards and produced inexpensive wireless products to expand capabilities of existing LANs. IEEE 802.11 b wireless products are widely accepted. Mobile ad hoc networks, a variant of the 802.11 standards, exist without the requirement for a wired infrastructure or host to provide routing, connectivity, and maintenance services. Because of the high variability of environments in which ad hoc networks operate, numerous routing protocols are proposed. Research indicates that these protocols are unsuited for efficient operation in multiple environments. In this investigation, the author examined the effect of multiple protocols on throughput and end-to-end delay in simulated ad hoc networks. The author selected the ad hoc on-demand distance vector (AODV) and dynamic source routing (DSR) routing protocols for this research. The outcomes from the simulations conducted indicated increased end-to-end delay and reduced packet throughput as a result of the mixed populations of the AODV and DSR ad hoc routing protocols. The results also indicated that increasing node density and velocity improved packet throughput and reduced end-to-end delay