1,723,278 research outputs found
Optimisation of IrDA IrLAP link access protocol
No full textThe widespread installation of millions of Infrared
Data Association (IrDA) infrared (IR) ports in mobile devices for wireless communication applications necessitates for throughput performance optimization of the IR links at the IrDA link access protocol (IrLAP) link layer. For IrDA connectivity, link-layer throughput optimization is important for any line bit-error
rate (BER). The paper provides a mathematical model with
which we derive a simple equation linking IrLAP throughput with physical and link-layer parameters. Simple equations for optimum values of window size and frame length for maximum link-layer throughput as a function of BER are derived. A study of the importance of parameters such as link minimum turnaround time and -timer time out period is presented. Finally, a protocol improvement that utilizes special supervisory frames (frames) to pass transmission control is proposed to deal with delays introduced by -timer expiration. Results indicate that employing
the special frame highly improves throughput performance
when optimum window and frame-size values are implemented
Wireless personal area networks and free-space optical links
No full textThis thesis is concerned with the link layer design of indoor (IrDA) and outdoor infrared links, as well as the performance of the higher layers of two major Wireless
Personal Area Network (WPAN) technologies: IrDA and Bluetooth. Recent advancesin wireless technology have made it possible to put networking technology into small portable devices. During the past few years, WPAN
technologies have been the subject of a tremendous growth both in research and development. Although many studies have been conducted on wireless links to address different issues on physical and link layers, wireless communications are still characterised by high error rates becauseof the frequently changing medium. On the other hand, performance studies of the higher layers are also very important. In this thesis, for the first time, a comprehensivestudy of the interactions betweenthe higher and the lower protocol layers of IrDA and Bluetooth has been carried out to improve the overall system performance. Mathematical models for the link layers are introduced for the infrared systems: infrared data association (IrDA) and free space optics (FSO). A model for the IrDA (indoor infrared) link layer is developed by considering the presence of bit errors. Based on this model, the effect of propagation delay on the link through put is investigated. An optimization study is also carried out to maximize the link
throughput. FSO (outdoor infrared) links are often characterized by high speed and long link distance. A mathematical model for the FSO link layer is also developed. Significant improvement of the link throughput is achieved by optimizing the link parameters. Based on the link layer model, the performance of the IrDA higher layers
(transport, session and application layers) is investigated. First, a mathematical model of TinyTP (transport protocol) is elaborated and subsequently verified by simulations. The effects of multiple connections and available buffer size are investigated. The
throughput at the TinyTP level is optimized for different buffer sizes. Subsequently, the session layer, including Object Exchange (OBEX) and IrDA Burst (IrBurst) protocols, is studied and modelled. The derived mathematical model is verified by simulation results. A set of protocol parameters and hardware selection guidelines is proposed to optimize the overall system performance while also keeping the hardware requirementto a minimum. Finally, two rapidly developing IrDA applications, IrDA financial messaging(IrFM) and IrDA simple connection (IrSC), are studied. IrFM is investigated by comparison to other digital payment technologies, while the performance of IrSC is compared in two different technical approaches. In order to improve the throughput and minimize the transmission delay for the
Bluetooth data applications, a systematic analysis is carried out for the Bluetooth Logical Link Control and Adaptation Layer Protocol (L2CAP). L2CAP is layered
above the Bluetooth link layer (Baseband) and is essential to Bluetooth data applications. A simple and intuitive mathematical model is developed to derive simple
equations for the L2CAP throughput and the average packet delay. The derived throughput equation, which is validated by simulations, takes into account bit errors as well as packet retry limits. Finally, a number of easy-to-implement performance enhancement schemes are proposed, including the optimum use of the protocol parameters
Analytical and simulation performance modelling of indoor infrared wireless data communications protocols
No full textThe Infrared (IR) optical medium provides an alternative to radio frequencies (RF) for low cost, low power and short-range indoor wireless data communications. Low-cost
optoelectronic components with an unregulated IR spectrum provide the potential for very high-speed wireless communication with good security. However IR links have a
limited range and are susceptible to high noise levels from ambient light sources. The Infrared Data Association (IrDA) has produced a set of communication protocol standards (IrDA I. x) for directed point-to-point IR wireless links using a HDLC (High-level Data Link Control) based data link layer which have been widely adopted. To address the requirement for multi-point ad-hoc wireless connectivity, IrDA have produced a new standard (Advanced Infrared -AIr) to support multiple-device non-directed IR Wireless Local Area Networks (WLANs). AIr employs an enhanced physical layer and a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) based MAC (Media Access Control) layer employing RTS/CTS (Request To Send / Clear To Send) media reservation. This thesis is concerned with the design of IrDA based IR wireless links at the datalink layer, media access sub-layer, and physical layer and presents protocol performance models with the aim of highlighting the critical factors affecting performance and providing recommendations to system designers for parameter settings and protocol enhancements to optimise performance. An analytical model of the IrDA 1.x data link layer (IrLAP Infrared Link Access -Protocol) using Markov analysis of the transmission window width providing saturation
condition throughput in relation to the link bit-error-rate (BER), datarate andprotocol parameter settings is presented. Results are presented for simultaneous optimisation of the data packetsize and transmission window size. A simulation model of the IrDA l. x protocol, developed with OPNETTM Modeler, is used for validation of analytical results and to produce non-saturation throughput and delay performance results. An analytical model of the AIr MAC protocol providing saturation condition utilisation
and delay results in relation to the number of contending devices and MAC protocol parametersis presented.Results indicate contention window size values for optimum
utilisation. The effectiveness of the AIr contention window linear back-off process is examined through Markov analysis. An OPNET simulation model of the Alf protocol is
used for validation of the analytical model results and provides non-reservation throughput and delay results. An analytical model of the IR link physical layer is presented and derives expressions for signal-to-noise ratio (SNR) and BER in relation to link transmitter and receiver
characteristics, link geometry, noise levels and line encoding schemes. The effect of third user interference on BER and resulting link asymmetry is also examined, indicating the minimum separation distance for adjacent links. Expressions for BER are linked to the data link layer analysis to provide optimum throughput results in relation to physical layer propertiesandlink distance
Link layer protocol performance of indoor infrared wireless communications
No full textThe 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
Portrait of Irda Childs Knight
No full textIrda Childs (later Irda Knight) entered Jacksonville State Teachers College as a freshman in Winter 1936.https://digitalcommons.jsu.edu/lib_ac_histimg_1930/1617/thumbnail.jp
Управління ПК за допомогою IrDA-передавача
No full textРобота присвячена створенню програмного пакету для використання у навчальному процесі.
Дипломна робота складається із вступу, двох розділів, висновків, списку використаних джерел та додатків.
У першому розділі розкривається поняття інтерфейсу IrDA, застосування інфрачервоного випромінювання, наведені приклади схем IrDA-інтерфейсу. Описано фізичні основи інтерфейсу IrDA та його програмний протокол.
У другому розділі дипломної роботи описано програму SlyControl, її налаштування та підключення нового скрипта, для управління ПК. А також описано програмні засоби для Linux
Performance modelling and enhancement of wireless communication protocols
No full textIn 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
RANCANG BANGUN PENGENALAN IDENTITAS MENGGUNAKAN IrDA (DESIGN OF USER IDENTIFICATION USING IrDA)
Full text linkABSTRAKSI: Akhir-akhir ini banyak perangkat yang di lengkapi dengan perangkat IrDA untuk memudahkan komunikasi antar device, misalkan handphone, PDA, laptop dan printer. Desktop PC sebenarnya sudah mendukung komunikasi IrDA pada motherboardnya hanya komponen pengirim dan penerima sinyal (LED dan photodioda) IrDAnya tidak langsung tersedia. Desktop PC dapat berkomunikasi dengan perangkat lain melalui inframerah jika kita menambahkan modul IrDA pada port Infrared yang terdapat pada motherboardnya.Desktop PC dapat digunakan dalam berbagai hal untuk membantu kehidupan manusia, salah satunya adalah untuk mengenali identitas pengguna. Pada umumnya untuk mengenali identitas terdapat username dan password untuk authentikasi user yang ada.Pada proyek akhir ini penyusun mencoba untuk mendayagunakan Handphone untuk menggantikan username yang dikenali dan di tambahkan password untuk tiap user sehingga handphone dapat dikenali sebagai penggambaran seorang user yang ingin berinteraksi dengan sebuah system.Untuk mengganti username penyusun mencoba untuk mengambil nomor IMEI dari perangkat handphone dan password sebagai interaksi user pemegang handphone untuk query pada database. Jika query tersebut menghasilkan sebuah data maka dapat disimpulkan bahwa user telah dikenali dan sebaliknya user tidak dianggap sebagai user yang sah jika nomor IMEI dan password tidak menghasilkan data pada query.Kata Kunci : ABSTRACT: Latterly a lot of peripheral which in induing Irda peripheral to facilitate communications usher device, for example handphone, PDA, laptop and printer. Desktop PC in fact have supported communications Irda, but the component of transmitter and receiver (LED and Photodioda) made available Indirect . Desktop PC earn to communicate with other;dissimilar peripheral through infra-red if we enhance module Irda at port Infrared on motherboard.Desktop PC earn used by in so many matter to assist human life, one of them is is to recognize consumer identity. Generally to recognize identity, there are username and password for user existing authentication .At this final project we try for purpose Handphone to replace username recognized and enhancing password to every user so that handphone earn recognized as depiction of a user interaction want to with a system.To change username, compiler try to take number IMEI from peripheral of handphone and password as interaction of user of handle handphone for query at database. If the query yield a inferential data hence that user have been recognized conversely user is not considered to be a valid user if number of IMEI and Password do not yield data at query.Keyword
Irda Knight, JSTC 1935-1936 Freshman 4
No full textIrda Knight was a Freshman at Jacksonville State Teachers College 1935-1936. (circa 1935-1936)https://digitalcommons.jsu.edu/lib-ac-histimg/2498/thumbnail.jp
Implementation of IrLAP Based on IrDA
No full textAbstractInfrared wireless communication plays an important role in wireless communication as its unique characteristic. The Infrared Data Association (IrDA) is a nonprofit international organization whose goal is to develop adopted specifications especially suited for low cost, short range, cross-platform, and point-to-point infrared wireless communications at a wide range of speeds. These standards have been implemented on various computer platforms and more recently have become available for many embedded applications. In this paper, we present the framework of IrDA stack first, and then describe the operating framework of IR Link Access Protocol (IrLAP), including the frame standard and the running process. Finally discuss the software design method based-on this framework
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