Indoor location tracking using RSSI readings from a single Wi-Fi access point

This paper describes research towards a system for locating wireless nodes in a home environment requiring merely a single access point. The only sensor reading used for the location estimation is the received signal strength indication (RSSI) as given by an RF interface, e.g., Wi-Fi. Wireless signal strength maps for the positioning filter are obtained by a two-step parametric and measurement driven ray-tracing approach to account for absorption and reflection characteristics of various obstacles. Location estimates are then computed using Bayesian filtering on sample sets derived by Monte Carlo sampling. We outline the research leading to the system and provide location performance metrics using trace-driven simulations and real-life experiments. Our results and real-life walk-troughs indicate that RSSI readings from a single access point in an indoor environment are sufficient to derive good location estimates of users with sub-room precision. Gergely V. Záruba is an Assistant Professor of Computer Science and Engineering at The University of Texas at Arlington (CSE@UTA). He has received the Ph.D. degree in Computer Science from The University of Texas at Dallas in 2001, and the M.S. degree in Computer Engineering from the Technical University of Budapest, Department of Telecommunications and Telematics, in 1997. Dr. Záruba’s research interests include wireless networks, algorithms, and protocols, performance evaluation, current wireless and assistive technologies. He has served on many organizing and technical program committees for leading conferences and has guest edited journals. He is a member of the IEEE and its Communications Society. Manfred Huber is an Assistant Professor of Computer Science and Engineering at The University of Texas at Arlington (CSE@UTA). He received his M.S. and Ph.D. degrees in Computer Science from the University of Massachusetts, Amherst in 1993 and 2000, respectively. He obtained his “Vordiplom” from the University of Karlsruhe, Germany in 1990. Dr. Huber is the co-director of the Robotics and of the Learning and Planning Laboratory at CSE@UTA. His research interests are in reinforcement learning, autonomous robots, cognitive systems, and adaptive human-computer interfaces. He is a member of the IEEE, the ACM, and the AAAI. Farhad A. Kamangar is a Professor of Computer Science and Engineering at The University of Texas at Arlington (CSE@UTA). He has received the Ph.D. and M.S. degrees in Electrical Engineering from The University of Texas at Arlington in 1980 and 1977 respectively. He received his B.S. degree from the University of Teheran, Iran in 1975. Dr. Kamangar’s research interests include image processing, robotics, signal processing, machine intelligence and computer graphics. He is a member of the IEEE and the ACM. Imrich Chlamtac is the President of CREATE-NET and the Bruno Kessler Professor at the University of Trento, Italy and has held various honorary and chaired professorships in USA and Europe including the Distinguished Chair in Telecommunications Professorship at the University of Texas at Dallas, Sackler Professorship at Tel Aviv University and University Professorship at the Technical University of Budapest. In the past he was with Technion and UMass, Amherst, DEC Research. Dr. Imrich Chlamtac has made significant contribution to various networking technologies as scientist, educator and entrepreneur. Dr. Chlamtac is the recipient of multiple awards and recognitions including Fellow of the IEEE, Fellow of the ACM, Fulbright Scholar, the ACM Award for Outstanding Contributions to Research on Mobility and the IEEE Award for Outstanding Technical Contributions to Wireless Personal Communications. Dr. Chlamtac published close to four hundred refereed journal, book, and conference articles and is listed among ISI’s Highly Cited Researchers in Computer Science. Dr. Chlamtac is the co-author of four books, including the first book on Local Area Networks (1980) and the Amazon.com best seller and IEEE Editor’s Choice Wireless and Mobile Network Architectures, published by John Wiley and Sons (2000). Dr. Chlamtac has widely contributed to the scientific community as founder and Chair of ACM Sigmobile, founder and steering committee chair of some of the lead conferences in networking, including ACM Mobicom, IEEE/SPIE/ACM OptiComm, CreateNet Mobiquitous, CreateNet WiOpt, IEEE/CreateNet Broadnet, IEEE/CreateNet Tridentcom and IEEE/CreateNet Securecomm conferences. Dr. Chlamtac also serves as the founding Editor in Chief of the ACM/URSI/Springer Wireless Networks (WINET), the ACM/Springer Journal on Special Topics in Mobile Networks and Applications (MONET).     

Multibuffer delay line architectures for efficient contentionresolution in optical switching nodes

This paper proposes an efficient contention resolution switching architecture which can serve as the basis for all-optical switching nodes. The presented solution builds on fiber delay lines used as temporary optical storage and 2×2 space photonic switches, a solution principle also known as Quadro or switched delay lines (SDLs). The efficiency of SDLs is fundamentally linked to its storage capacity, i.e., the length of the fiber delay lines, while its cost depends on the number of 2×2 photonic switches, i.e., the number of stages in the switch. This work presents a solution that makes use of multibuffer fiber delay lines which allow multiple packets to be concurrently stored (propagated) on each line. With a novel switch control, it is shown that this solution increases the total storage capacity and significantly improves switch and network performance, without increasing the number of the 2×2 switches in the system, i.e., its cost     

The wireless segment of enterprise networking

Changes in the business environment are transforming people's mode of operation and work habits. Many corporate employees spend time away from their assigned wired phones but are still in their offices or other locations of the company. Companies are starting to be aware of the opportunities that mobility offers to increase productivity, provide better customer service, and lead to future cost savings. Thus, companies are increasingly adding mobility solutions to their existing networks and continuously integrate them as seamlessly as possible. The emerging answer is enterprise wireless telephony, which, unlike its public cellular counterpart, is free of air time charges. This article describes the enterprise wireless technologies. We briefly introduce the location system and then focus on communications services with solutions for single- and multilocation enterprise     

Call performance for a PCS network

It is well known that, due to the mobility of a portable and limited channel availability, calls of portables may not be completed due to being blocked or terminated during the call initiation or the handover process. The characteristics of the call-completion and call-holding times for both a complete call and an incomplete call are of critical importance for establishing the actual billing process in the PCS network. We derive the call-completion probability (hence, call-dropping probability) and the effective call-holding time distributions for complete/incomplete calls with a general cell-residence time and a general call-holding time are analyzed, and general computable formulas are obtained. We show that when call-holding times are Erlang distributed, easy-to-compute formulas for the probability of a call completion and the expected effective call-holding times for both a complete call and an incomplete call can be derived     

BIONETS: Bio-Inspired Networking for Pervasive Communication Environments

This paper presents BIONETS, which is a novel bio-inspired approach to the design of localized services in pervasive communication/computing environments. Conventional networking approaches are not suitable for such scenarios, where they face three main issues, namely: 1) heterogeneity, 2) scalability, and 3) complexity. The proposed solution draws inspiration from the living world in terms of 1) evolutionary paradigms able to drive the adaptation process of autonomic services and 2) social paradigms for the provisioning of the necessary cooperation mechanisms. The net result is the introduction of autonomic self-evolving services that are able to adapt to localized needs and conditions while ensuring the maintenance of a purposeful system. Such a system requires scalable support from the communication standpoint. In networking terms, this results in the introduction of a two-tier architecture based on localized opportunistic exchanges of information. The presented approach is able to achieve better scalability properties when compared to more conventional communication approaches     

Module count-based overflow-control scheme for UMTS high-speed downlink packet access

In the universal mobile telecommunication system, the user equipment (UE) communicates with all cells in the active set through the air interface. Multiple radio links between the UE and the cells may reduce the transmission speed due to interference. In high-speed downlink packet access (HSDPA), only one serving cell is selected in the active set for high-speed downlink transmission. When the radio link quality between the serving cell and the UE degrades below some threshold, the best cell (in terms of the radio characteristics) in the active set is selected as the new serving cell and the UE switches from the old serving cell to the new serving cell. This action is referred to as frame synchronization. The frame-synchronization information may be delivered through more than one wireless transmission, which introduces long delay for the frame-synchronization process. In this paper, we propose an overflow-control scheme with module count for HSDPA, which guarantees that the frame-synchronization information is delivered through one wireless transmission and that when the UE switches wireless link to the new serving cell, no packet frames are lost.     

Analysis of blocking probability for distributed lightpath establishment in WDM optical networks

In this paper, we analyze the blocking probability of distributed lightpath establishment in wavelength-routed WDM networks by studying the two basic methods: destination-initiated reservation (DIR) and source-initiated reservation (SIR). We discuss three basic types of connection blocking: 1) blocking due to insufficient network capacity; 2) blocking due to outdated information; and 3) blocking due to over-reservation. It is shown that the proposed models are highly accurate for both the DIR and the SIR methods, in both the regular and irregular network topologies, under the whole range of traffic loads.     

Modeling PCS networks under general call holding time and cellresidence time distributions

In a personal communication service (PCS) network, the call completion probability and the effective call holding times for both complete and incomplete calls are central parameters in the network cost/performance evaluation. These quantities will depend on the distributions of call holding times and cell residence times. The classical assumptions made in the past that call holding times and cell residence times are exponentially distributed are not appropriate for the emerging PCS networks. This paper presents some systematic results on the probability of call completion and the effective call holding time distributions for complete and incomplete calls with general cell residence times and call holding times distributed with various distributions such as gamma, erlang, hyperexponential, hyper-erlang, and other staged distributions. These results provide a set of alternatives for PCS network modeling, which can be chosen to accommodate the measured data from PCS field trials. The application of these results in billing rate planning is also discussed     

Characterizing the behaviour of high-speed interconnection systems with distributed control

In this paper, we consider very high-speed, connection-oriented communication in distributed systems where each node system has a limited-size queue for connection requests. An important example of this type of system is an HIPPI-based interconnection system of a supercomputer complex. For such systems, we present a distributed connection management policy and propose several possible service disciplines. We develop an analytic model to evaluate the interconnection system under different system configurations, connection management policies, and service disciplines. In this evaluation, we consider separately systems where nodes want to communicate with any one of a pool of identical servers, and systems where a node needs to access a specific one of a set of distinct servers.     

Time-spread multiple-access (TSMA) protocols for multihop mobileradio networks

This paper introduces a novel technique called protocol threading, yielding a deterministic protocol that gives a guaranteed upper bound on the transmission delay of each packet at every node in a multihop mobile network. By eliminating the maximum degree constraint, the new method improves upon existing time-spread multiple-access (TSMA)-type protocols while preserving the advantages of the deterministic operation and topology transparency. We introduce the protocol threading solution, derive the maximum delay bound in a mobile topology, and analyze the performance of the protocol