Showing papers on "Wireless published in 1999"

Antennas and Propagation for Wireless Communication Systems

Abstract: From the Publisher: This title introduces the basic concepts and specific applications of antennas and propagation to wireless systems, covering terrestrial and satellite radio systems in both mobile and fixed contexts. Includes: Illustrations of the significance and effect of the wireless propagation channelOverview of the fundamental electromagnetic principles underlying propagation and antennasBasic concepts of antennas and their application to specific wireless systemsPropagation measurement, modeling, and predication for fixed links for macrocells, microcells, picocells, and megacellsNarrowband and wideband channel modeling and the effect of the channel on communication system performanceMehtods that overcome and transform channel impairments to enhance performance using diversity, adaptive antennas, and equalizersExamples of real-world practical system problems of communications design and operationExtensive worked examplesEnd-chapter questionsTopical and relevant information for and about the wireless communications industry.

Cognitive radio for flexible mobile multimedia communications

Abstract: Wireless multimedia applications require significant bandwidth, some of which will be provided by third-generation (3G) services. Even with substantial investment in 3G infrastructure, the radio spectrum allocated to 3G will be limited. Cognitive radio offers a mechanism for the flexible pooling of radio spectrum using a new class of protocols called formal radio etiquettes. This approach could expand the bandwidth available for conventional uses (e.g. police, fire and rescue) and extend the spatial coverage of 3G in a novel way. Cognitive radio is a particular extension of software radio that employs model-based reasoning about users, multimedia content, and communications context. This paper characterizes the potential contributions of cognitive radio to spectrum pooling and outlines an initial framework for formal radio-etiquette protocols.

Simplified processing for high spectral efficiency wireless communication employing multi-element arrays

Abstract: We investigate robust wireless communication in high-scattering propagation environments using multi-element antenna arrays (MEAs) at both transmit and receive sites. A simplified, but highly spectrally efficient space-time communication processing method is presented. The user's bit stream is mapped to a vector of independently modulated equal bit-rate signal components that are simultaneously transmitted in the same band. A detection algorithm similar to multiuser detection is employed to detect the signal components in white Gaussian noise (WGN). For a large number of antennas, a more efficient architecture can offer no more than about 40% more capacity than the simple architecture presented. A testbed that is now being completed operates at 1.9 GHz with up to 16 quadrature amplitude modulation (QAM) transmitters and 16 receive antennas. Under ideal operation at 18 dB signal-to-noise ratio (SNR), using 12 transmit antennas and 16 receive antennas (even with uncoded communication), the theoretical spectral efficiency is 36 bit/s/Hz, whereas the Shannon capacity is 71.1 bit/s/Hz. The 36 bits per vector symbol, which corresponds to over 200 billion constellation points, assumes a 5% block error rate (BLER) for 100 vector symbol bursts.

Maximum ratio transmission

Abstract: This paper presents the concept, principles, and analysis of maximum ratio transmission for wireless communications, where multiple antennas are used for both transmission and reception. The principles and analysis are applicable to general cases, including maximum-ratio combining. Simulation results agree with the analysis. The analysis shows that the average overall signal-to-mise ratio (SNR) is proportional to the cross correlation between channel vectors and that error probability decreases inversely with the (L/spl times/K)th power of the average SNR.

Channel estimation for OFDM systems with transmitter diversity in mobile wireless channels

Abstract: Transmitter diversity is an effective technique to improve wireless communication performance. In this paper, we investigate transmitter diversity using space-time coding for orthogonal frequency division multiplexing (OFDM) systems in high-speed wireless data applications. We develop channel parameter estimation approaches, which are crucial for the decoding of the space-time codes, and we derive the MSE bounds of the estimators. The overall receiver performance using such a transmitter diversity scheme is demonstrated by extensive computer simulations. For an OFDM system with two transmitter antennas and two receiver antennas with transmission efficiency as high as 1.475 bits/s/Hz, the required signal-to-noise ratio is only about 7 dB for a 1% bit error rate and 9 dB for a 10% word error rate assuming channels with two-ray, typical urban, and hilly terrain delay profiles, and a 40-Hz Doppler frequency. In summary, with the proposed channel estimator, combining OPDM with transmitter diversity using space-time coding is a promising technique for highly efficient data transmission over mobile wireless channels.

Distributed quality-of-service routing in ad hoc networks

Abstract: In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.

Mobile Radio Communications

Abstract: From the Publisher: Mobile radio communications technology has progressed rapidly and it is now capable of the transmission of voice, data and image signals. This new edition explains the latest techniques employed in second and third generation systems. A comprehensive all-in-one mobile communication reference work, Mobile Radio Communications, Second Edition reflects the current state-of-the-art by featuring expanded and updated sections on voice compression techniques, interleaving and channel coding methods, quaternary frequency shift keying, continuous phase modulation methods, Viterbi equalisation and slow frequency hopping as well as extended coverage of the GSM system; and three new chapters on wireless multimedia, third generation systems and on WATM respectively. As in the first edition, this edition continues to cover important topics such as radio propagation, multiple access methods and, on a higher level, cordless telecommunications and teletraffic issues. This book will prove invaluable to mobile communication engineers, designers, researchers and students in the design, operation and research of second and third generation systems and wireless LANs.

Fair scheduling in wireless packet networks

Abstract: Fair scheduling of delay and rate-sensitive packet flows over a wireless channel is not addressed effectively by most contemporary wireline fair-scheduling algorithms because of two unique characteristics of wireless media: (1) bursty channel errors and (2) location-dependent channel capacity and errors. Besides, in packet cellular networks, the base station typically performs the task of packet scheduling for both downlink and uplink flows in a cell; however, a base station has only a limited knowledge of the arrival processes of uplink flows. We propose a new model for wireless fair-scheduling based on an adaptation of fluid fair queueing (FFQ) to handle location-dependent error bursts. We describe an ideal wireless fair-scheduling algorithm which provides a packetized implementation of the fluid mode, while assuming full knowledge of the current channel conditions. For this algorithm, we derive the worst-case throughput and delay bounds. Finally, we describe a practical wireless scheduling algorithm which approximates the ideal algorithm. Through simulations, we show that the algorithm achieves the desirable properties identified in the wireless FFQ model.

Scalable routing strategies for ad hoc wireless networks

Abstract: We consider a large population of mobile stations that are interconnected by a multihop wireless network. The applications of this wireless infrastructure range from ad hoc networking (e.g., collaborative, distributed computing) to disaster recovery (e.g., fire, flood, earthquake), law enforcement (e.g., crowd control, search-and-rescue), and military (automated battlefield). Key characteristics of this system are the large number of users, their mobility, and the need to operate without the support of a fixed (wired or wireless) infrastructure. The last feature sets this system apart from existing cellular systems and in fact makes its design much more challenging. In this environment, we investigate routing strategies that scale well to large populations and can handle mobility. In addition, we address the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video). In the wireless routing area, several schemes have already been proposed and implemented (e.g., hierarchical routing, on-demand routing, etc.). We introduce two new schemes-fisheye state routing (FSR) and hierarchical state routing (HSR)-which offer some competitive advantages over the existing schemes. We compare the performance of existing and proposed schemes via simulation.

Fundamentals of Convolutional Coding

Abstract: From the Publisher: Convolutional codes, among the main error control codes, are routinely used in applications for mobile telephony, satellite communications, and voice-band modems. Written by two leading authorities in coding and information theory, this book brings you a clear and comprehensive discussion of the basic principles underlying convolutional coding. This book can be used as a textbook for graduate-level electrical engineering students. It will be of key interest to researchers and engineers of wireless and mobile communication, satellite communication, and data communication.

Predictive distance-based mobility management for PCS networks

Abstract: This paper presents a mobile tracking scheme that exploits the predictability of user mobility patterns in wireless PCS networks. Instead of the constant velocity fluid-flow or the random-walk mobility model, a more realistic Gauss-Markov model is introduced, where a mobile's velocity is correlated in time to a various degree. Based on the Gauss-Markov model, a mobile's future location is predicted by the network based on the information gathered from the mobile's last report of location and velocity. When a call is made, the network pages the destination mobile at and around the predicted location of the mobile and in the order of descending probability until the mobile is found. A mobile shares the same prediction information with the network and reports its new location whenever it reaches some threshold distance away from the predicted location. We describe an analytical framework to evaluate the cost of mobility management for the proposed predictive distance-based scheme. We then compare this cost against that of the regular, non-predictive distance-based scheme, which is obtained through simulations. Performance advantage of the proposed scheme is demonstrated under various mobility and call patterns, update cost, page cost, and frequencies of mobile location inspections.

Radio Propagation for Modern Wireless Systems

Abstract: From the Book: PREFACE: Preface The commercial success of cellular mobile radio since its initial implementation in the early 1980s has led to an intense interest among wireless engineers in understanding and predicting radio propagation characteristics within cities, and even within buildings. In this book we discuss radio propagation with two goals in mind. The first is to provide practicing engineers having limited knowledge of propagation with an overview of the observed characteristics of the radio channel and an understanding of the process and factors that influence these characteristics. The second goal is to serve as text for a master's-level course for students intending to work in the wireless industry. Books on modern wireless applications typically survey the issues involved, devoting only one or two chapters to radio channel characteristics, or focus on how the characteristics influence system performance. Now that the wireless field has grown in scope and size, it is appropriate that books such as this one examine in greater depth the various underlying topics that govern the design and operation of wireless systems. The material for this book has grown out of tutorials given by the author to engineering professionals and a course on wireless propagation given by the author at Polytechnic University as part of a program in wireless networks. It also draws upon the 15 years of experience the author and his students have had in understanding and predicting propagation effects. Cellular telephones gave the public an active role in the use of the radio spectrum as opposed to the previous role of passive listener. This social revolution in the use of theradiospectrum ultimately changed governmental views of its regulation. Driven by the requirement to allow many users to operate in the same band, cellular telephones also created a technical revolution through the concept of spectral reuse. Systems that do not employ spectral reuse avoid interference by operating in different frequency bands and are limited in performance primarily by noise. In these systems, lack of knowledge of the propagation conditions can be compensated for by increasing the transmitted power, up to regulatory limits. In contrast, the concept of spectral reuse acknowledges that in commercially successful systems, interference from other users will be the primary factor limiting performance. In designing these systems, it is necessary to balance the desired signal for each user against interference from signals intended for other users. Finding the balance requires knowledge of the radio channel characteristics. Chapter 1 is intended to introduce the student reader to the concept of spectrum reuse and in the process to give examples of how the propagation characteristics influence the balance between desired signal and interference, and thereby influence system design. As in all chapters, examples are discussed to illustrate the concepts, and problems are included at the end of the chapter to give the students experience in applying the concepts. In modern systems, the radio links are about 20 kilometers or less, the antennas that create the links lie near to or among the buildings or even inside the buildings, and the wavelength is small compared to the building dimensions. As a result, the channel characteristics are strongly influenced by the buildings as well as by vegetation and terrain. In this environment, signals propagate from one antenna to the other over multiple paths that involve the processes of reflection and transmission at walls and by the ground and the process of diffraction at building edges and terrain obstacles. The multipath nature of the propagation makes itself felt in a variety of ways that have challenged the inventiveness of communication engineers. Although initially a strong limitation on channel capacity, engineers have begun to find ways to harness the multipath signals so as to achieve capacities that approach the theoretical limit. However, each new concept for dealing with multipath calls for an even deeper understanding of the statistical characteristics of the radio channel. In Chapter 2 we describe many of the propagation effects that have been observed in various types of measurements, ranging from path loss for narrowband signals, to angle of arrival and delay spread for wideband transmission. As in other chapters, an extensive list of references is cited to aid the professional seeking a detailed understanding of particular topics. For the student reader, this chapter serves as an introduction to the types of measurements that are made, the methods used to process the data, and some of the statistical approaches used to represent the results. Understanding the measurements, their processing, and their representation also serves to guide the theoretical modeling described in subsequent chapters. The level of presentation assumes that the reader has had an undergraduate course in electromagnetics with exposure to wave concepts. The presentation does not attempt to derive the propagation characteristics from Maxwell's equations rigorously; rather, the goal is to avoid vector calculus. The reader's background is relied on for acceptance of some wave properties; other properties are motivated through heuristic arguments and from basic ideas, such as conservation of power. For example, in Chapter 3 we start with the fundamental properties of plane waves and call on the reader's background in transmission lines when discussing reflection and transmission at the ground and walls. Wherever possible in this and following chapters, the theoretical results are compared to measurements. Thus plane waves are used to model observed interference effects, which are referred to as fast fading, and to model Doppler spreading. Plane wave properties and conservation of power are used in Chapter 4 to justify the properties of spherical waves radiated by antennas and to motivate the ray description of reflection at material surfaces. By accounting for these reflections, propagation on line-of-sight paths in urban canyons is modeled. Circuit concepts are used to obtain the reciprocity of propagation between antennas, and to derive expressions for path gain or loss. Diffraction at building edges is an important process in wireless communications. It allows signals to reach subscribers who would otherwise be shadowed by the buildings. Because the reader is not expected to be familiar with this process, Chapter 5 explores diffraction in some detail. For simplicity, the scalar form of the Huygens-Kirchhoff integral is use as a starting point. We first use it to give physical meaning to the Fresnel ellipsoid about a ray, which is widely employed in propagation studies to scale physical dimensions. The geometrical and uniform forms of the fields diffracted by an absorbing half screen are derived. In these expressions we identify a universal component that applies to diffraction by any straight building edge or corner and a diffraction coefficient whose specific form is dependent on the nature of the edge. Diffraction coefficients for several types of edges and corners are given without derivation. Using heuristic ray arguments, the results obtained for plane waves are generalized to spherical waves radiated by antennas and to multiple edges. These results are cast in terms of path gain or loss, which is convenient for wireless applications. Chapter 6 formulates the problem of average path loss in residential environments in terms of multiple diffraction past rows of buildings. Relying on the Huygens-Kirchhoff formulation, the diffraction problem is solved for various ranges of base station and subscriber antenna height. These results show how the frequency, average building height, and row separation influence the range dependence and height gain of the signal. This approach to diffraction is used in Chapter 7 to investigate the effects of randomness in building construction on shadow fading. Chapter 7 also makes use of diffraction to examine the effects of terrain and vegetation on the average path loss. Propagation predictions that make use of a geometrical description of individual buildings are discussed in Chapter 8. Various ray-based models that incorporated the processes of reflection and diffraction at buildings have been developed to make such site-specific predictions. Their accuracy has been evaluated primarily by comparing predictions against measurements of the small area average received signal. However, the ray models have started to be used to predict higher-order channel statistics, such as time delay and angle spread, through Monte Carlo simulations. This approach can generate values for the statistical descriptors of the radio channel that are employed in advanced communication systems and show how these values depend on the distribution of building size and shape in different cities.

Combined array processing and space-time coding

Abstract: The information capacity of wireless communication systems may be increased dramatically by employing multiple transmit and receive antennas. The goal of system design is to exploit this capacity in a practical way. An effective approach to increasing data rate over wireless channels is to employ space-time coding techniques appropriate to multiple transmit antennas. These space-time codes introduce temporal and spatial correlation into signals transmitted from different antennas, so as to provide diversity at the receiver, and coding gain over an uncoded system. For large number of transmit antennas and at high bandwidth efficiencies, the receiver may become too complex whenever correlation across transmit antennas is introduced. This paper dramatically reduces encoding and decoding complexity by partitioning antennas at the transmitter into small groups, and using individual space-time codes, called the component codes, to transmit information from each group of antennas. At the receiver, an individual space-time code is decoded by a novel linear processing technique that suppresses signals transmitted by other groups of antennas by treating them as interference. A simple receiver structure is derived that provides diversity and coding gain over uncoded systems. This combination of array processing at the receiver and coding techniques for multiple transmit antennas can provide reliable and very high data rate communication over narrowband wireless channels. A refinement of this basic structure gives rise to a multilayered space-time architecture that both generalizes and improves upon the layered space-time architecture proposed by Foschini (see Bell Labs Tech. J., vol.1, no.2, 1996).

IP-flow classification in a wireless point to multi-point (PTMP) transmission system

Abstract: An IP flow classification system is used in a wireless telecommunications system. The IP flow classification system groups IP flows in a packet-centric wireless point to multi-point telecommunications system. The classification system includes: a wireless base station coupled to a first data network; one or more host workstations coupled to the first data network; one or more subscriber customer premise equipment (CPE) stations in wireless communication with the wireless base station over a shared bandwidth using a packet-centric protocol; and one or more subscriber workstations coupled to each of the subscriber CPE stations over a second network; a resource allocation device optimizes end-user quality of service (QoS) and allocates shared bandwidth among the subscriber CPE stations; an analyzing and scheduling device analyzes and schedules internet protocol (IP) flow over the shared wireless bandwidth. The analyzing device includes the above IP flow classifier that classifies the IP flow. The classifier can include a device for associating a packet of an existing IP flow with the IP flow. The classifier can include a QoS grouping device that groups a packet of a new IP flow into a QoS class grouping. The QoS grouping device can include a determining device that determines and takes into account QoS class groupings for the IP flow. The QoS grouping device can include an optional differentiated services (Diff Serv) device that takes into account an optional Diff Servs field priority marking for the IP flow.

Calibration for wireless location system

Abstract: An external calibration method comprises the steps of transmitting a first reference signal from a reference transmitter; receiving the first reference signal at first and second receiver systems; (10-2A-10-2C); determining a first error value by comparing a measured TDOA value with a theoretical TDOA value associated with the known locations of the receiver systems and the known location of the reference transmitter; and utilizing the first error value to correct subsequent TDOA measurements associated with a mobile transmitter to be located. An internal calibration method comprises the steps of injecting a comb signal into the first receiver system; utilizing the comb signal to obtain an estimate of the manner in which the transfer function varies across the bandwidth of the first receiver system; and utilizing the estimate to mitigate the effects of the variation of the first transfer function on the time measurement made by the first receiver system.

Apparatus and method for remote troubleshooting, maintenance and upgrade of implantable device systems

Abstract: A programmer operating in association with a diverse number of implantable medical devices (IMDs) is in a bi-directional operable data, voice and video communications with a remote web-based expert data center. The programmer is in telemetric wireless communications with the IMDs. The data center is equipped to manage the operational and functional aspects of the programmer remotely thus importing expertise to the patient environment. Specifically the communications scheme is scalable and adaptable to enable high-speed interactions between the programmer and the remote center across various communications media. The remote center is able to remotely assess, monitor, evaluate for failure or conduct other performance checks on the programmer to implement a remote solution to those problems. Specifically, by utilizing the robust communication scheme integrated with the remote web-based expert data center, the system enables a real-time deployment of executable software commands to manage the programmer by remotely monitoring, updating software, performing remote repairs or replacement of components and alerting operators to significant problems before they become critical to the optimal performance and reliability of the programmer.

Method for effectively implementing a wireless television system

Abstract: A method for effectively implementing a wireless television system comprises a wireless base station that processes and combines various program sources to produce a processed stream. A transmitter then responsively transmits the processed stream as a broadcast output stream to various portable wireless display devices for flexible viewing at variable remote locations.

Satellite positioning system augmentation with wireless communication signals

Abstract: A method and apparatus for processing position information from satellite positioning system satellites and from cellular based communication signals In one example of a method according to the invention, a SPS receiver receives SPS signals from at least one SPS satellite This SPS receiver is coupled to and typically integrated with a communication system which receives and transmits messages in a cell based communication system In this method, a message is transmitted in the cell based communication signals between a communication system and a first cell based transceiver A time measurement which represents a time of travel of a message in the cell based communication signals between the cell based transceiver and the communication system is determined Another time measurement which represents a time of travel of the SPS signals is also determined A position of the SPS receiver is determined from a combination of at least the time measurement which represents the time of travel of a message in the cell based communication signals and from a time measurement which represents a time of travel of the SPS signals The cell based communication signals are capable of communicating data messages in a two-way direction in one embodiment between the cell based transceiver and the communication system

Wireless Location in CDMA Cellular Radio Systems

Abstract: From the Publisher: Wireless Location in CDMA Cellular Radio Systems investigates methods for wireless location in CDMA networks and analyzes their performances. Techniques for measuring location parameters (AoAs, ToAs, etc.) are presented along with algorithms for calculating position from those parameters. Several impairments to accurate location are covered and analyzed including multipath propagation, non-line-of-sight propagation, and multiple-access interference. Many of the topics in this book are also applicable to FDMA- and TDMA-based communication networks.

Joint multipath-Doppler diversity in mobile wireless communications

Abstract: We introduce a new approach for achieving diversity in spread-spectrum communications over fast-fading multipath channels. The RAKE receiver used in existing systems suffers from significant performance degradation due to the rapid channel variations encountered under fast fading. We show that the Doppler spread induced by temporal channel variations in fact provides another means for diversity that can be further exploited to combat fading. We develop the concept of Doppler diversity and propose a framework that exploits joint multipath-Doppler diversity in an optimal fashion. Performance analysis shows that even the relatively small Doppler spreads encountered in practice can be leveraged into significant diversity gains via our approach. The framework is applicable in several mobile wireless multiple access systems and can provide substantial performance improvement over existing systems.

BLAST training : Estimating Channel Characteristics for High-Capacity Space-Time Wireless

Abstract: BLAST (Bell Labs Layered Space-Time) is a multiple-antenna communication scheme whose outage capacity in a Rayleigh at fading environment grows linearly with the minimum of the number of transmit and receive antennas, with no increase in bandwidth or transmitted power. Based on its knowledge of the matrix of propagation coeecients, the receiver performs two critical operations: nulling and cancellation, that in eeect create independent virtual subchannels. Assume that the receiver estimates the propagation matrix from a known set of transmitted training signals, and then uses the estimate as though it were correct for nulling and cancellation. How much training is needed for satisfactory operation? The optimal training signals are orthogonal with respect to time among the transmit antennas, and each transmit antenna is fed equal energy. Errors in estimating the propagation matrix manifest themselves as crosstalk among the virtual subchannels. If its magnitude is too large, the crosstalk constitutes an outage event that is independent of the primary outage event (e.g., that the value of the propagation matrix cannot support the transmission rate). We show that the training interval required to control the probability of the estimation-error induced outage is approximately proportional to the number of transmit antennas, and is independent of the number of receive antennas. Contrary to what is implied by their names, the operations of nulling and cancellation are, in fact, robust with respect to estimation errors. Our results have an interesting implication for BLAST, either in a mobile environment , or for TDMA, where both training and data transmission have to occur within a xed interval: if one wishes to maximize the overall transmission rate, then the number of transmit antennas should be chosen such that half of the interval is used for training, and half of the interval for data transmission.

Scheduling data broadcast in asymmetric communication environments

Abstract: With the increasing popularity of portable wireless computers, mechanisms to efficiently transmit information to wireless clients are of significant interest. The environment under consideration is asymmetric in that the information server has much more bandwidth available, as compared to the clients. In such environments, often it is not possible (or not desirable) for the clients to send explicit requests to the server. It has been proposed that in such systems the server should broadcast the data periodically. One challenge in implementing this solution is to determine the schedule for broadcasting the data, such that the wait encountered by the clients is minimized. A broadcast schedule determines what is broadcast by the server and when. In this paper, we present algorithms for determining broadcast schedules that minimize the wait time. Broadcast scheduling algorithms for environments subject to errors, and systems where different clients may listen to different number of broadcast channels are also considered. Performance evaluation results are presented to demonstrate that our algorithms perform well.

Wireless area network communications module for utility meters

Abstract: A communications module that permits remote meter reading of a utility meter via a wireless modem that communicates using data packet networks along a communications system, such as ARDIS. The communications module is a microprocessor-based transmitter/receiver which receives data collection requests from a system server, initiates data collection from a utility meter, and reports the data back to a host computer system residing, for example, at a central office. Preferably, session-based communication using the meter protocol is implemented between the communications module and the meter, and packet switching is used between the communications server and the communications module through the network.

The Mobile Communications Handbook

Abstract: From the Publisher: The Mobile Communications Handbook covers the entire field - from principles of analog and digital communications to cordless telephones, wireless local area networks (LANs), and international technology standards. The amazing scope of the handbook ensures that it will be the primary reference for every aspect of mobile communications. Organized in two sections, The Mobile Communications Handbook first introduces the basic principles of analog and digital communications. Consisting of tutorial articles, this section provides background information and technical details, offering a solid foundation for the spectrum of mobile communications technology. The second part of the handbook consists of articles covering such topics as cellular mobile radio, personal communication systems, user location and addressing, wireless data, wireless LANs, and technology standards. New to the Second Edition: Discussions on: Rayleigh fading channelsSpace-time processingRadiolocation techniquesEnhancements in second generation systemsWireless video communicationsWireless ATMEvolving third generation standards Plus updates on: Wireless dataPower controlChannel assignmentDiversity techniquesError correction codingPseudonoise sequences

Multiple input data management for wireless location-based applications

Abstract: Multiple location finding equipment (LFE) inputs are used to enhance the location information made available to wireless location-based applications. In one implementation, the invention is implemented in a wireless network including an MSC (112) for use in routing communications to or from wireless stations (102), a network platform (114) associated with the MSC (112), and a variety of LFE systems (104, 106, 108 and 110). A Location Finding System (LFS) (116) in accordance with the present invention is resident on the platform (114). The LFS (116) receives location information from the LFEs (104, 106, 108 and 110) and provides location information to wireless location based applications (118). In this regard, the LFS (116) can receive input information at varying time intervals of varying accuracies and in various formats, and can provide standardized outputs to the applications (118), for example, depending on the needs of the applications (118). Multiple inputs may also be co-processed for enhanced accuracy.

Method and apparatus for exclusively pairing wireless devices

Abstract: A method and system for enabling wireless devices to be paired or permanently associated by a user or a network administrator. The method and system utilize well known public key cryptography and machine unique identifiers to establish a secure channel and associate the devices with eachother. This is extremely useful for associating a wireless headset with a telephone or associating a wireless mouse with a computer.

System, method and apparatus for secure transmission of confidential information

Abstract: A system, method and apparatus for establishing a secure wireless radio communications link (IR) between two devices that minimizes the exposure of sensitive information to third party interception is disclosed The secure link is established by first establishing an infrared link (IR) between the two devices for the exchange of sensitive information, such as encryption information Subsequent communications (RF) would then have the benefit of encryption protection, establishing the secure wireless radio communications link

Methods and systems for providing television related services via a networked personal computer

Abstract: A set top box is provided that interfaces a television and a personal computer that is connected to the Internet. The set top box includes a wireless remote control receiver that receives user commands from a wireless remote control unit. A radio frequency transceiver that transmits computer commands to the personal computer that is connected to the Internet in response to the user commands and that receives data that is generated from the Internet via the personal computer in response to the computer commands. A video processing system that processes the received data for display on a television and a television interface that displays the processed received data on the television.

On the capacity formula for multiple input-multiple output wireless channels: a geometric interpretation

Abstract: The capacity of multiple input, multiple output wireless channels is computed for Ricean channels The novelty is a geometrical (ray-tracing) interpretation of the MIMO channel capacity formula to find array geometries which greatly enhance channel capacity compared to SISO systems

System and method for determining the position of a wireless cdma transceiver

Abstract: An apparatus and method to determine a position of a mobile wireless transceiver. The invention merges GPS position location and wireless communication technologies to achieve a precise position location in dense urban and other environments when line-of-sight to the satellites is somewhat obscured. The inventive apparatus and method use signals from only two GPS satellites (60, 70, 80, 90) and the serving terrestrial base station. In a most general sense, the inventive method includes the steps of receiving at a base station (10) a first signal transmitted from a first GPS satellite and a second signal transmitted from a second GPS satellite. The mobile's transmitter (200) and receiver (100) are adapted to receive these GPS signals as well and transmit a third signal to the base station in response thereto. The base station (10) receives the third signal and uses it to calculate the position of the wireless unit (20).