Wireless personal area networks and free-space optical links

This 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

Wireless personal area networks and free-space optical links

This 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.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Coexistence and interference mitigation for WPANs and WLANs from traditional approaches to deep learning: a review

More and more devices, such as Bluetooth and IEEE 802.15.4 devices forming Wireless Personal Area Networks (WPANs) and IEEE 802.11 devices constituting Wireless Local Area Networks (WLANs), share the 2.4 GHz Industrial, Scientific and Medical (ISM) band in the realm of the Internet of Things (IoT) and Smart Cities. However, the coexistence of these devices could pose a real challenge—co-channel interference that would severely compromise network performances. Although the coexistence issues has been partially discussed elsewhere in some articles, there is no single review that fully summarises and compares recent research outcomes and challenges of IEEE 802.15.4 networks, Bluetooth and WLANs together. In this work, we revisit and provide a comprehensive review on the coexistence and interference mitigation for those three types of networks. We summarize the strengths and weaknesses of the current methodologies, analysis and simulation models in terms of numerous important metrics such as the packet reception ratio, latency, scalability and energy efficiency. We discover that although Bluetooth and IEEE 802.15.4 networks are both WPANs, they show quite different performances in the presence of WLANs. IEEE 802.15.4 networks are adversely impacted by WLANs, whereas WLANs are interfered by Bluetooth. When IEEE 802.15.4 networks and Bluetooth co-locate, they are unlikely to harm each other. Finally, we also discuss the future research trends and challenges especially Deep-Learning and Reinforcement-Learning-based approaches to detecting and mitigating the co-channel interference caused by WPANs and WLANs

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

Wireless Network Communications Overview for Space Mission Operations

The mission of the On-Board Wireless Working Group (WWG) is to serve as a general CCSDS focus group for intra-vehicle wireless technologies. The WWG investigates and makes recommendations pursuant to standardization of applicable wireless network protocols, ensuring the interoperability of independently developed wireless communication assets. This document presents technical background information concerning uses and applicability of wireless networking technologies for space missions. Agency-relevant driving scenarios, for which wireless network communications will provide a significant return-on-investment benefiting the participating international agencies, are used to focus the scope of the enclosed technical information