Showing papers on "Wi-Fi array published in 2000"

Wireless integrated network sensors

Abstract: W ireless integrated network sensors (WINS) provide distributed network and Internet access to sensors, controls, and processors deeply embedded in equipment, facilities, and the environment. The WINS network represents a new monitoring and control capability for applications in such industries as transportation, manufacturing, health care, environmental oversight, and safety and security. WINS combine microsensor technology and low-power signal processing, computation, and low-cost wireless networking in a compact system. Recent advances in integrated circuit technology have enabled construction of far more capable yet inexpensive sensors, radios, and processors, allowing mass production of sophisticated systems linking the physical world to digital data networks [2–5]. Scales range from local to global for applications in medicine, security, factory automation, environmental monitoring, and condition-based maintenance. Compact geometry and low cost allow WINS to be embedded and distributed at a fraction of the cost of conventional wireline sensor and actuator systems. WINS opportunities depend on development of a scalable, low-cost, sensor-network architecture. Such applications require delivery of sensor information to the user at a low bit rate through low-power transceivers. Continuous sensor signal processing enables the constant monitoring of events in an environment in which short message packets would suffice. Future applications of distributed embedded processors and sensors will require vast numbers of devices. Conventional methods of sensor networking represent an impractical demand on cable installation and network bandwidth. Processing at the source would drastically reduce the financial, computational, and management burden on communication system

Application-specific protocol architectures for wireless networks

Abstract: In recent years, advances in energy-efficient design and wireless technologies have enabled exciting new applications for wireless devices. These applications span a wide range, including real-time and streaming video and audio delivery, remote monitoring using networked microsensors, personal medical monitoring, and home networking of everyday appliances. While these applications require high performance from the network, they suffer from resource constraints that do not appear in more traditional wired computing environments. In particular, wireless spectrum is scarce, often limiting the bandwidth available to applications and making the channel error-prone, and the nodes are battery-operated, often limiting available energy. My thesis is that this harsh environment with severe resource constraints requires an application-specific protocol architecture, rather than the traditional layered approach, to obtain the best possible performance. This dissertation supports this claim using detailed case studies on microsensor networks and wireless video delivery. The first study develops LEACH (Low-Energy Adaptive Clustering Hierarchy), an architecture for remote microsensor networks that combines the ideas of energy-efficient cluster-based routing and media access together with application-specific data aggregation to achieve good performance in terms of system lifetime, latency, and application-perceived quality. This approach improves system lifetime by an order of magnitude compared to general-purpose approaches when the node energy is limited. The second study develops an unequal error protection scheme for MPEG-4 compressed video delivery that adapts the level of protection applied to portions of a packet to the degree of importance of the corresponding bits. This approach obtains better application-perceived performance than current approaches for the same amount of transmission bandwidth. These two systems show that application-specific protocol architectures achieve the energy and latency efficiency and error robustness needed for wireless networks. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Enhancements to the RADAR User Location and Tracking System

Abstract: We address the problem of locating users inside buildings using a radio-frequency (RF) wireless LAN. A previous paper presented the basic design and a limited evaluation of a user-location system we have developed. In this paper, we analyze shortcomings of the basic system, and develop and evaluate solutions to address these shortcomings. Additionally, we describe several new enhancements, including a novel access point-based environmental profiling scheme, and a Viterbi-like algorithm for continuous user tracking and disambiguation of candidate user locations. Using extensive data collected from our deployment, we evaluate our system’s performance over multiple wireless LAN technologies and in different buildings on our campus. We also discuss significant practical issues that arise in implementing such a system. Our techniques are implemented purely in software and are easily deployable over a standard wireless LAN.

Microwave and Rf Design of Wireless Systems

Abstract: From the Publisher: This book offers a quantitative and design-oriented presentation of the analog RF aspects of modern wireless telecommunications and data transmission systems from the antenna to the baseband level. It takes an integrated approach to topics such as antennas and proagation, microwave systems and circuits and communication systems.

Wireless medium access control protocols

Abstract: Technological advances, coupled with the flexibility and mobility of wireless systems, are the driving force behind the Anyone, Anywhere, Anytime paradigm of networking. At the same time, we see a convergence of the telephone, cable and data networks into a unified network that supports multimedia and real-time applications like voice and video in addition to data. Medium access control protocols define rules for orderly access to the shared medium and play a crucial role in the efficient and fair sharing of scarce wireless bandwidth. The nature of the wireless channel brings new issues like location-dependent carrier sensing, time varying channel and burst errors. Low power requirements and half duplex operation of the wireless systems add to the challenge. Wireless MAC protocols have been heavily researched and a plethora of protocols have been proposed. Protocols have been devised for different types of architectures, different applications and different media. This survey discusses the challenges in the design of wireless MAC protocols, classifies them based on architecture and mode of operation, and describes their relative performance and application domains in which they are best deployed.

Beyond 3G: wideband wireless data access based on OFDM and dynamic packet assignment

Abstract: The rapid growth of wireless voice subscribers, the growth of the Internet, and the increasing use of portable computing devices suggest that wireless Internet access will rise rapidly over the next few years. Rapid progress in digital and RF technology is making possible highly compact and integrated terminal devices, and the introduction of sophisticated wireless data software is making wireless Internet access more user-friendly and providing more value. Transmission rates are currently only about 10 kb/s for large cell systems. Third-generation wireless access such as WCDMA and the evolution of second-generation systems such as TDMA IS-136+, EDGE, and CDMA IS-95 will provide nominal bit rates of 50-384 kb/s in macrocellular systems. This article discusses packet data transmission rates of 2-5 Mb/s in macrocellular environments and up to 10 Mb/s in microcellular and indoor environments as a complementary service to evolving second- and third-generation wireless systems. Dynamic packet assignment for high-efficiency resource management and packet admission; OFDM at the physical layer with interference suppression, space-time coding, and frequency diversity; as well as smart antennas to obtain good power and spectral efficiency are discussed in this proposal. Flexible allocation of both large and small resources also permits provisioning of services for different delay and throughput requirements.

Method and apparatus for wireless telecommunications system that provides location-based information delivery to a wireless mobile unit

Abstract: A wireless telecommunications system uses location or position information of a wireless mobile unit to initiate the sending of location-specific information to travelers. As position information is received, it is compared to prestored position information of a remote location, such as an airport. As the traveler approaches the remote location, and gets within a certain distance the remote location, information such as airline arrival information is retrieved and sent to the wireless mobile unit of the traveler. Thus, useful information tied to the position of the wireless mobile unit, such as airline or traffic information for example, is obtained.

Intelligent network selection based on quality of service and applications over different wireless networks

Abstract: A system and method for selecting a wireless network is disclosed. The method relates to selecting a wireless network from plurality of wireless networks. A variation of the invention includes selecting a new platform from a plurality of platforms offered by the current service provider according to a service request from the wireless device. The method comprises determining a requested service associated with the wireless device, determining whether one of the plurality of wireless networks can provide the requested service, and, if one of the plurality of wireless networks can provide the requested service, choosing the one wireless network of the plurality of wireless networks. The method further involves using a variety of parameters in determining which wireless network to choose for servicing the requested service from the wireless device.

Emerging mobile and wireless networks

Abstract: W ith the increasing use of small portable computers, wireless networks, and satellites, a trend to support computing on the move has emerged—this trend is known as mobile computing or nomadic computing [3]. Also referred to as anytime/anywhere computing, mobile computing has several interesting and important applications for business (such as instant claim processing and e-commerce), telecommunications and personal communications, national defense (tracking troop movements), emergency and disaster management, real-time control systems, remote operation of appliances, and in accessing the Internet. Since a user may not maintain a fixed position in such environments, the mobile and wireless networking support allowing mobile users to communicate with other users (fixed or mobile) becomes crucial. A possible scenario may involve several different networks that can support or can be modified to support mobile users. When dealing with different wireless networks, a universal mobile device should be able to select the network (LAN, the Internet, PCS, or satellite) that best meets user requirements. Wireless and mobile networks have provided the flexibility required for an increasingly mobile workforce. As shown in Figure 1(a), the worldwide number of cellular, GSM, and PCS subscribers increased from 140 million in 1996 to over 300 million in 1999 and is expected to grow to 650 million by 2001 (see www.gsmdata.com). In the U.S., capital investment increased from $6.3 billion in 1990 to $66.8 billion in 1999 and service revenues were up from $4.5 billion to $38.7 billion in 1999 (see www.wow-com.com) as shown in Figure 1(b). During the same period, the average local monthly bill diminished from $80 to $39 as shown in Figure 1(c), indicating the technological maturity and the tremendous competition among service providers. Many general remarks can be made about wireless systems. First, the channel capacity typically available in wireless systems is much lower than what is Upkar Varshney and Ron Vetter

System, method, and article of manufacture for wireless enablement of the world wide web using a wireless gateway

Abstract: A system, method and article of manufacture are provided for selection and formatting of web content for remote viewing. User-defined information is received and used to retrieve content from one or more web sites. The retrieved content is aggregated at a network server located remotely from the user. The aggregated content is formatted at the network server for display on a wireless device. The formatted content is transmitted to a wireless device for display on the wireless device.

Secure wireless electronic-commerce system with wireless network domain

Abstract: A method of conducting transactions in a wireless electronic commerce system, where the system comprises a wireless network operator certification authority (15) having a root public key certificate and at least one attribute authority (404, 405, 406) having a digital certificate that is dependent from the root public key certificate. The attribute authority is accessible by a wireless client device (11) via a wireless network. The digital certificate is delivered from the attribute authority to the wireless device, the attribute authority is verified to the wireless client device using the digital certificate and the root public key certificate preloaded in the wireless client device under authority of the wireless network operator. An attribute (software, service, right/permission or other content item) is delivered to the wireless client device over the wireless network and ultimately enabled at the wireless client device.

Method and system for brokering bandwidth in a wireless communications network

Abstract: A method and system for brokering bandwidth in a wireless communications network includes receiving a request for a wireless service at a geographic region. An availability of the wireless service is determined at the geographic region. A response to the request is generated based on the availability of the wireless service. The response includes one or more terms for the wireless service.

Location privacy feature for wireless mobile stations and method of operation

Abstract: In a wireless mobile station of the type having a position locating system capable of determining the location of the wireless mobile station, there is disclosed control circuitry capable of being selectively set to disable the transmission of information concerning the location of the wireless mobile station. The control circuitry also comprises a directory of telephone numbers of locations authorized to receive information concerning the location of the wireless mobile station. Also disclosed is control circuitry capable of receiving a code that causes the wireless mobile station to transmit information concerning the location of the wireless mobile station. Also disclosed are methods for selectively disabling the transmission of information concerning the location of the wireless mobile station.

Method and system for wireless QOS agent for all-IP network

Abstract: A wireless quality of service (QoS) agent for an all-Internet Protocol (IP) network. The QoS agent couples to an all-IP network. The coupling means includes communication means for transfer of information between the agent and a QoS manager of the all-IP network. The agent is also able to seamlessly extend QoS support for multimedia applications from wireline to wireless and control QoS of the multimedia applications sent over wireless connections on the all-IP network.

Method and system for automated optimization of antenna positioning in 3-d

Abstract: A method for engineering management and planning for the design of a wireless communications network in three-dimensions (3-D) combines computerized organization, database fusion, and radio frequency (RF) site-specific planning models. The method enables a designer to keep track of wireless system performance throughout the process of pre-bid design, installation and maintenance of a wireless system. Using a database of information that defines the desired environment (1002), predictions (1001) of antenna coverage, system coverage and interference, and other wireless system performance criteria, such as frame error rate and network throughput, can be made. Watch points (1004) are created to ensure, in real time, that any modifications (1006) to the design of the wireless system do not degrade the performance of the system with respect to the watch point locations.

System and method for tracking movement of a wireless device

Abstract: The present invention is a system and method for tracking movement of a wireless device. The tracking can be done during a wireless communication session between the wireless device and a called party. The present invention comprises a location system that can generate initial location information pinpointing an initial location of the wireless device. The location system can generate subsequent location information pinpointing subsequent locations of the wireless device. The system further comprises a location server that can determine whether the subsequent location information should be provided to the called party in accordance with a rule. Based on the subsequent location information, the movement of the wireless device can be tracked by the called party. In the preferred embodiment, the wireless device is a wireless telephone and the called party is a public safety answering point. In the preferred embodiment, the subsequent location can be generated at regular intervals, and the subsequent location can be provided to the public safety answering point when the subsequent location information indicates that the wireless device has traveled a specific distance.

Wireless optical transmissions with white colored LED for wireless home links

Abstract: We propose a wireless optical communication system with white colored LEDs for a wireless home link (WHL). The white colored LEDs have a high power output and are regarded as lamps for the next generation. In the proposed system, this device is used for a wireless home link. The proposed system is suitable for private networks such as consumer communication networks. From numerical and simulation results, it is confirmed that the proposed system is available and the problems to be solved are made clear.

Wireless communication system for location based schedule management and method therefor

Abstract: A wireless communication system for location based schedule management ( 10 ) includes a plurality of wireless communication devices ( 40 ), including a wireless communication device ( 32 ) and a backup wireless communication device ( 47 ); a system controller ( 24 ) for generating a message; a RF transmitter ( 26 ) for transmitting the message ( 34 ) to the plurality of wireless communication devices ( 40 ); and an application server ( 76 ). The application server ( 76 ) includes a server memory ( 152 ) for storing an event location ( 134 ) and one or more event criteria parameters ( 129 ), a server processor ( 150 ) for processing a current location ( 122 ) of the wireless communication device ( 32 ); and a server event management application ( 82 ) for comparing the current location ( 122 ) with the event location ( 134 ). The server processor ( 150 ) sends a server command ( 84 ) to the system controller ( 24 ) in response to the comparison of the current location ( 122 ) and the event location ( 134 ) exceeding the event criteria parameters ( 129 ). The system controller ( 24 ) sends an update message ( 36 ) to the backup wireless communication device ( 47 ) in response to the server command ( 84 ).

In a wireless system, a method of selecting an application while receiving application specific messages and user location method using user location awareness

Abstract: A method of selecting an application in a wireless device and a user location method are provided. In the method of selecting an application, specific messages are received from a wireless station. The application specific messages are specific to services provided via a wireless station transmitting the application specific messages. The application specific messages have an application specific identifier identifying a specific application and data corresponding to the specific application. It is determined whether an application is present in the wireless device that corresponds to the received application specific identifier. If it is determined that the corresponding application is absent in the wireless device, the correspondingly received data is ignored. In the user location method that is used in a wireless system, locations and user identities of users of wireless devices are registered. The wireless devices are capable of roaming through the wireless system when the wireless devices enter into coverage areas of wireless stations in the system. A user location awareness application uses the registered locations and user identities of the wireless devices.

Multi-protocol wireless communication apparatus and method

Abstract: A scalable, multi-protocol mobile switching center (200) in a wireless communications network provides communications control for digital and analog wireless communication devices (110, 112, 115, 116, 118, 140) including devices that operate according to GSM and IS-31 standards. The hardware and software architecture of the switching center is designed so that processing that is unique to a particular protocol is performed at the lowest possible level, and remaining processing can use generic procedures. The switching center incorporates a home location register and visitor location register that are used in conjunction with software applications to determine the protocol of mobile communications devices using the wireless communication network. The mobile switching center can be used to provide a large scale distributed wireless network or a small scale wireless network. The switching center can also be used as an adjunct to a private branch exchange to provide in-building wireless services and call control. Graphical user interfaces make the wireless communications network easy to maintain.

Method and system for measuring data quality of service in a wireless network using multiple remote units and a back end processor

Abstract: The present invention provides for a method and system for measuring data quality of service in a wireless network using multiple peripatetic (i.e. mobile) and/or stationary, unattended, position, and performance instruments (PUPPIs) that are remotely controlled by a back end processor. In some embodiments of the invention, the data service whose quality is measured relates to wireless Internet access, e-commerce transactions, wireless messaging, or push technologies. In other embodiments of the invention, the system includes an element that is located within the wireless network infrastructure, for example, at the WAP gateway to monitor the wireless data protocol and to perform benchmarking measurements.

System and method for providing high speed wireless media access

Abstract: A system and method for providing high speed wireless media access is disclosed. A local transceiver is provided, which is capable of transmitting data via a transmit path while receiving a feedback signal via a receive path. The local transmitter is connected to a feedback generator for generating and transmitting a feedback signal in response to receiving data from a wireless transceiver. A feedback detector is also connected to the local transceiver for detecting feedback signals received from other wireless transceivers. When a feedback signal is detected, data associated with the signal is decoded. The wireless transceivers then transmit a feedback signal within the series of wireless transceivers in order to stop the transmission of data until a destination of the data is determined. A destination address associated with a destination wireless transceiver is then identified and the transmission of feedback signals by all wireless transceivers within the system then ceases, except from the identified destination wireless transceiver.

Method and system for queuing traffic in a wireless communications network

Abstract: A method and system for queuing traffic in a wireless network includes receiving a stream of packets for transmission in the wireless network. Each packet includes a flow identifier and is assigned to one of the plurality of virtual groups based on the flow identifier. The virtual groups include discrete transmission resources. Each packet is queued in an assigned virtual group for transmission in the wireless network.

A Software System for Locating Mobile Users: Design, Evaluation, and Lessons

Abstract: We have built a software system, RADAR, to locate mobile users connected to an in-building radiofrequency (RF) wireless LAN. RADAR uses signal strength information extracted from the wireless network interface, in conjunction with a Radio Map of the building, to determine location. Over the past year we have deployed this system in multiple buildings on our campus using two different wireless LAN technologies and two widely used operating systems. This experience has led us to identify some shortcomings of the basic RADAR system and fundamental limitations in the way wireless network hardware is abstracted in contemporary operating

Power-conscious design of wireless circuits and systems

Abstract: The great importance of power consciousness is well understood in mobile wireless communications. However, with growing experience the fundamental principles underlying power conscious design of RF circuits, systems, and networks are only now becoming known. Using as example ultralow-power wireless devices for messaging such as paging receivers and wireless sensor networks, the first part of this paper presents the relationship between current consumption and dynamic range of low-noise amplifiers, mixers, oscillators, and active filters. The second part of the paper covers issues of modulation, protocols, and networking that would be required in dense networks of wireless sensors, which communicate using very little energy. These ideas are expected to find use in most forms of digital wireless communications.

Communication system, and mobile communication device, portable information processing device, and data communication method used in the system

Abstract: A mobile communication device includes a unit for establishing a wireless link for a wireless communication with an external device, a unit for, via the wireless link, sending a signal to the external device to start software installed therein, a unit for, via the wireless link, receiving display data generated by software from the external device, and a unit for displaying on a screen the display data received.

System for determining wireless coverage using location information for a wireless unit

Abstract: A system for determining coverage in a wireless communications systems uses location information for a wireless unit and collects information on communications between the wireless unit and the wireless communications system in association with the location information. The wireless communications system determines and/or receives location information for the wireless unit along with other information associated with the location information. The information by location can be used to represent the coverage of a geographic region. For example, during communications between a serving base station and a wireless unit, the serving base station could receive and/or determine signal quality measurements of a forward link and/or of a reverse link at a particular location. Additionally, neighboring base stations can monitor the communications and determine and/or receive location information for the location of the wireless unit along with the information associated with or corresponding to the location of the wireless unit. The associated information can be linked with additional parameters, such as wireless unit type, wireless unit identity, frequency, operating conditions and/or base station identity. In accordance with other aspects of the present invention, the information and/or measurements stored by location can be used to derive additional and/or different information by location or determine how the wireless communications system communicates with a wireless unit at a location, for example the base station to service the wireless unit at the location. A wireless unit in a location or range of location(s) could be served by a serving base station(s) at a certain transmit power and frequencies given certain operating conditions or parameters, such as time, weather, traffic load, path loss and/or interference level. A change in operating condition could trigger a dynamic change in the RF coverage provided by the serving base station(s) and/or neighboring base stations to the wireless unit(s) in the location or range of locations.

Methods and apparatus for a flexible wireless communication and cellular telephone system

Abstract: A wireless communication system including flexible wireless handsets with modular electronic components selected for operation within multiple systems. The units may be configured for removable connection to a variety of cartridges to provide a versatile communication device. A cartridge may be selected for the replacement of one or more existing cartridges within the handset to provide varying degrees of flexibility including the selection of a different featureset for the handset and compatible operation within different wireless systems. Methods are further provided for upgrading and reconfiguring cellular telephones and wireless communication devices for operation within different systems. A flexible wireless telephone with an original removable cartridge may include later-substituted cartridges to improve or change the featureset of the telephone, and may also enable a user to replace the internal electronics of a handset with different internal electronics for use within a different wireless system. A consumer may be thus provided with extended use the same flexible wireless telephone handset yet still migrate to a new wireless system by installing cartridges with desired featuresets within the selected wireless telephone system(s).

Multiple wireless communication protocol methods and apparatuses

Abstract: A wireless device is provided with a first wireless transceiver and a second wireless transceiver operative in a coordinated manner and coupled to at least one controller manager. The first wireless transceiver transmits and receives signals in accordance with a first protocol to and from a first network device of a first wireless network communicatively coupled to the apparatus, and the second wireless transceiver transmits and receives signals in accordance with a second protocol to and from a second network device of a second wireless network communicatively coupled to the apparatus. The wireless device is further provided with a network manager to coordinate the transmit and receive operations of the first wireless transceiver and said the second wireless transceiver in order to enable the wireless device to communicate contemporaneously with the first and second wireless networks. The network manager may be further configured to coordinate the first and second network devices of the first and second wireless networks. This coordination may include, for example, selection of network devices of either the first or the second network as dominant devices that operationally dominate network devices of the other network. The coordination further includes notifying at least one of the dominated devices, from time to time, to temporarily suspend signal transmission in order to proactively avoid frequency interference with the dominant devices.