Showing papers on "Wireless WAN published in 1995"

Broadband wireless system and network architecture providing broadband/narrowband service with optimal static and dynamic bandwidth/channel allocation

Abstract: A wireless broadband communication system architecture is structured to provide an array of narrowband and broadband services to an end user on demand. The bandwidth of delivery is dynamically adjusted to deliver and satisfy service requirements by utilizing the appropriate bandwidth on demand. Bandwidth-on-demand is provided in accord with the invention by rearranging spectrum allocations so that a particular band spectrum is convertibly used to accomplish different purposes depending on present allocations and active applications of the system. The communications system is designed to utilize wireless communication for end point delivery to both fixed and potable terminals. The system supplies basic telephone service, wireless ISDN service, wireless data service, wireless multimedia service and various other wireless broadband service including types of interactive and broadcast video.

Wireless personal communications: what is it?

Abstract: This article attempts to identify different issues and to put many of the activities in wireless into a framework that can provide perspective on what is driving them, and perhaps even yield some indication of where they appear to be going in the future The technologies and systems that are currently providing, or are proposed to provide, wireless communications services can be grouped into about seven relatively distinct groups All of the technologies and systems are evolving as technology advances and perceived needs change Some trends are becoming evident in the evolutions The different groups and evolutionary trends are explored along with factors that influence the characteristics of members of the groups The grouping is generally with respect to scale of mobility and communications applications or modes Different design compromises are evident in the different technologies and systems The evidence suggests that the evolutionary trajectories are aimed toward at least three large groups of applications or services, namely, high-tier PCS (current cellular radio), high-speed wireless local-area networks (WLANS), and low-tier PCS (an evolution from several of the current groups) It is not clear to what extent several groups, eg, cordless telephones, paging, and wide area data, will remain after some merging with the three large groups >

Method for reducing unnecessary traffic over a computer network

Abstract: Standard protocols, such as those commonly used on LAN networks, are used to connect nodes to an enterprise network via a wide area wireless network. Within the appropriate protocol stacks, the standard protocols are optimized by filtering some packets, eliminating and reducing the size of other fields and substituting still other fields to reduce the size of the data packets. The optimized data packets can be transmitted over the wireless WAN increasing WAN efficiency. The optimization is accomplished by inserting an additional optimization layer into the protocol stack between the existing layers. The optimization layer accepts the normal protocol signals generated by the surrounding layers and generates outputs which mimic protocol layers which the surrounding layers expect. Consequently, the optimization layer operates transparently with respect to the existing protocol stack layers.

Wireless network planning tool

Abstract: A novel and improved method and apparatus for planning a wireless telecommunications network. An electronic representation of wireless telecommunications system can be configured within a given market area and the operation of that wireless telecommunications system simulated. The simulation is performed using a set of databases that contain terrain and population information associated with the market area over which the wireless network in configured. To perform the simulation a composite propagation loss matrix and a demand and service vector are generated using the terrain and population information, as well as the configuration of the wireless telecommunications network. Once the composite propagation loss matrix and the demand and service vector are generated an analysis of the reverse link is performed. Subsequently, an analysis of the forward link is performed. During both the reverse and forward link analysis the multiple iterations of analysis are performed until a stable result is achieved. Upon completion of the reverse and forward link analysis, the results of the simulation are displayed in a graphical manner for examination.

BAHAMA: a broadband ad-hoc wireless ATM local-area network

Abstract: We describe the theory, design and ongoing prototyping of a wireless ATM LAN/PBX capable of supporting mobile users with multi-Mb/s access rates and multi-Gb/s aggregate capacities. Our proposed LAN consists of network nodes called portable base stations (PBS) providing microcell coverage. The PBSs are designed to be low-cost, compact and high-speed and can be relocated conveniently. We employ a concept of ad-hoc networking in the layout of the PBS-to-PBS interconnection. That is, the PBSs can be distributed in an arbitrary topology to form a backbone network and can be reconfigured with relative ease. The PBS-to-PBS backbone links are high-speed (Gb/s) for supporting high system capacity. Although they can either be wired or wireless, our emphasis is on wireless implementations. The user-to-PBS links, on the other hand, are primarily for mobile access (e.g., 2-20 Mb/s) and therefore are wireless. Wired connections from stationary users to PBSs are also possible. Typical mobile users are assumed to be laptops or notebook computers. Services supported include conventional data applications (e.g., over TCP/IP or SPX/IPX) as well as multimedia (video, voice and data) applications with QoS (quality-of-service) guarantees. A "aireless ATM" concept is proposed so as to provide seamless internetworking with other wired ATM local and wide-area networks. Algorithms and control in our network are highly distributed for simple implementations and ease of mobility management. A new wireless VP/VC concept and a homing algorithm are described to provide ATM cell routing and connections in the network. PBS hardware and software architectures are discussed. Call management, network management and signaling are designed for simplicity, high performance and modular implementations. A fast network restoration scheme is proposed to cope with the potential link or node failures in the ad-hoc network. Error control is addressed taking the unreliable wireless links into consideration. Finally, a prototyping project called BAHAMA (broadband ad hoc ATM anywhere) for demonstrating this network concept is briefly outlined.

Network management and control issues in multimedia wireless networks

Abstract: Discusses some typical multimedia applications and services that might be expected to use future wireless and combined wireless/wired networks. These include, among others, multimedia teleconferencing, the electronic newspaper, and nomadic computing. The author then describes control questions to be addressed in the mixed wireless/wired environment and control problems arising in the wireless network environment itself. Included are questions such as admission control, dynamic bandwidth control, flow control, handoff control, and resource allocation, among others. >

Wireless computer network communication system and method having at least two groups of wireless terminals

Abstract: A wireless computer network communication system for use in an environment in which plural groups can perform network communication at the same time. A channel controller receives a requirement of starting network communication from a computer, controls a wireless channel sensor, and detects a received signal. The wireless channel detector detects which wireless channel is employed by one or more other networks and the channel controller determines the wireless channel to be employed by its own group and also controls the transceiver. The computer starts the network communication through a network controller. The network controller controls the transceiver for transmitting and receiving data by use of the wireless channel, and the same further controls the transmitting/receiving of the requirements and the data from the computer.

A wireless broadband ad-hoc ATM local-area network

Abstract: We describe the theory, design and ongoing prototyping of a wireless ATM LAN/PBX capable of supporting mobile users with multi-Mb/s access rates and multi-Gb/s aggregate capacities. Our proposed LAN consists of network nodes called Portable Base Stations (PBS) providing microcell coverage. The PBSs are designed to be low-cost, compact and high-speed and can be relocated conveniently. We employ a concept of ad-hoc networking in the layout of the PBS-to-PBS interconnection. That is, the PBSs can be distributed in an arbitrary topology to form a backbone network and can be reconfigured with relative ease. The PBS-to-PBS backbone links are high-speed (Gb/s) for supporting high system capacity. Although they can either be wired or wireless, our emphasis is on wireless implementations. The user-to-PBS links, on the other hand, are primarily for mobile access (e.g., 2-20 Mb/s) and therefore are wireless. Wired connections from stationary users to PBSs are also possible. Typical mobile users are assumed to be laptops or notebook computers. Services supported include conventional data applications (e.g., over TCP/IP or SPX/IPX) as well as multimedia (video, voice and data) applications with QoS (Quality-of-Service) guarantees. A “wireless ATM” concept is proposed so as to provide seamless internetworking with other wired ATM local and wide-area networks. Algorithms and control in our network are highly distributed for simple implementations and ease of mobility management. A new wireless VP/VC concept and a Homing Algorithm are described to provide ATM cell routing and connections in the network. PBS hardware and software architectures are discussed. Call management, network management and signaling are designed for simplicity, high performance and modular implementations. A fast network restoration scheme is proposed to cope with the potential link or node failures in the ad-hoc network. Error control is addressed taking the unreliable wireless links into consideration. Finally, a prototyping project called BAHAMA (Broadband Ad Hoc ATM Anywhere) for demonstrating this network concept is briefly outlined.

Two-way wireless data network having a transmitter having a range greater than portions of the service areas

Abstract: A two-way data network includes a broadcast control sub-network and a cellular data sub-network. The broadcast control sub-network includes a few high-power radio transmitters broadcasting into a large service area. The cellular data sub-network covers the large service area by a number of base stations each servicing a relatively small area. The wireless terminals of the two-way data network monitors the messages in a broadcast control channel at pre-assigned periodic time slots and remain in "sleep" mode at other times. A packet radio transceiver in the wireless terminal sends data to, and receives data from, the cellularized base stations. The broadcast control sub-network is used to notify the subscriber the receipt of a message. In responding to the notification, the location of the subscriber's wireless terminal is make known, thereby eliminating conventional tasks such as location and mobility management tasks and allowing wireless terminals to be low power. Communication between the cellular base stations and the wireless terminals achieves high data rate, low latency and high capacity.

Trends in local wireless networks

Abstract: Pahlavan (1985) published an article entitled "Wireless office information networks". That article examined spread spectrum, standard radio and infrared (IR) technologies for intra-office wireless networking. In May of that year the FCC released the ISM (industrial, scientific, and medical) bands for spread spectrum local communications. Although ISM bands are not restricted to any specific application, wireless local area networks (LANs) were one of the most prominent applications that were envisioned by the rule makers in the FCC. Since 1985, many small start-up companies, as well as small groups in larger companies, have started to develop wireless LANs. The present paper provides a sequel to Pahlavan by providing an overview of the past and present of the wireless LAN industry, as well as a perspective of the future directions that encompass a vision for a ubiquitous local wireless computing environment that leads to a fusion of communications and computation. >

Interference analysis of nonpersistent CSMA with hidden terminals in multicell wireless data networks

Abstract: In multi-cell wireless networks such as wireless LANs under standardization (IEEE 802.11 and ETSI's HIPERLAN), we must consider interference interaction among different cells as there are a very limited number of channels for operation. We introduce a theoretical analysis to evaluate CSMA in multicell wireless networks by taking hidden terminals, interference, and cell-overlapping into account. Both nonpersistent CSMA and CSMA with a 4-way handshaking as the IEEE 802.11 draft are considered in this paper.

Radio personal communications system and method for allocating frequencies for communications between a cellular terminal and a base station

Abstract: Transceiver frequency and optionally power level are allocated to a radio personal communications system which includes a base station connected to a wire telephone network and a cellular terminal operating within a region of a wide area cellular network to minimize interference between communications over the wide area cellular network and communications between the base station and the cellular terminal. The same cellular terminal may thus be used to communicate over the lower cost wire network when within range of the base station and over the wide area cellular network otherwise. The frequency for communications between the cellular terminal and the base station are optionally assigned by the operator of the wide area cellular network so appropriate frequencies and power levels can be assigned for base stations, to minimize same channel interference with the wide area cellular network.

The design & implementation of a hybrid handover protocol for multi-media wireless LANs

Abstract: c ACM 1995. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commerical advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association of Computing Machinery. To copy otherwise or to republish will require a fee and/ or speci c permission. Abstract

Mobile wireless network system simulation

Abstract: This paper describes an advanced simulation environment which is used to examine, validate, and predict the performance of mobile wireless network systems. This simulation environment overcomes many of the limitations found with analytical models, experimentation, and other commercial network simulators available on the market today. We identify a set of components which make up mobile wireless systems and describe a set of flexible modules which can be used to model the various components and their integration. These models are developed using the Maisie simulation language. By modeling the various components and their integration, this simulation environment is able to accurately predict the performance bottlenecks of a multimedia wireless network system being developed at UCLA, determine the trade-off point between the various bottlenecks, and provide performance measurements and validation of algorithms which are not possible through experimentation and too complex for analysis.

Wireless terminal having digital radio processing with automatic communication system selection capability

Abstract: A wireless terminal utilizing digital radio processing utilizes stored program control to allow the wireless terminal to operate in a plurality of disposed wireless communication systems. In particular, the digital radio processing with appropriate stored program control operates in a plurality of wireless communication system by selectively and controllably enabling selection of frequency, channel bandwidth, modulation type, channel coding and source coding operational components appropriate to the communication system that the wireless unit is to operate in. A function control enables the wireless terminal to actively seek out and search for availability of wireless communications system in which it may operate.

Wireless data: systems, standards, service

Abstract: Wireless data products and services being proposed today include exotic mixes of services and technologies: packet transport over cellular circuits, facsimile service over Cellular Digital Packet Data (CDPD), voice and video over wireless LANs, and everything in between. Data networking terms that seem to have a clear meaning—data-link, network and transport layers; circuit-mode and datagram; connection-less and connection-oriented—in fact have meaning only in context. Thus TCP, a reliable packet transport protocol, is being used in CDMA circuit-mode data to provide a reliable data-link layer for the errorprone wireless link. IP datagrams will be transported over cellular links using dedicated channels with call establishment, possibly per packet. Market demands for timely solutions, competition between alternative technologies and the plethora of alternative fora for standards development are driving wireless data into fragmented directions. The primary constraints come from the limited spectrum, the need for security in the presence of mobility and the size and weight of mobile terminals and devices. Often the optimization for the latter constraints is sacrificed at the altar of the former drivers. Based upon our experience and work with standards and systems we attempt to put wireless data into perspective. We compare and contrast major services and products and identify the choices that were made and why.

Method and apparatus for improving the throughput of a local area network

Abstract: A method and system for improving local area network throughput and thereby reducing traffic on the network hardware, allowing more workstations to be serviced by fewer servers. A further method for creating a bi-directional distributed processing system for cooperatively improving the local area network performance. In the preferred embodiment, a method is presented allowing workstations on a network to cache locally data normally retrieved from a network server or host machine.

An authentication system and method for preventing wireless communication fraud

Abstract: An improved wireless communication system including a process and apparatus for detecting and preventing fraudulent usage of wireless communication service. The improvement includes a central database in communication with wireless communication networks and paging networks, with the central database being capable of determining when a wireless terminal is being fraudulently used in a wireless communication network. The central database is further capable of sending a paged message to the subscriber notifying the subscriber of the suspected fraudulent usage.

Effective wireless communication through application partitioning

Abstract: The comparatively severe network constraints imposed by mobile wireless computing require more careful management of communication resources than is typically necessary in the wired network. The performance characteristics of the wireless network are affected by a number of factors such as changes in location, environmental noise, cost constraints, and contention with other users. In addition, since even simple applications can quickly consume all the bandwidth on a slow link the contention introduced between applications will be significant. These dynamic changes in limited resources increase the difficulty of effective network management for a mobile device. This paper describes an approach in which the application specifies its interactions with the mobile device through a high-level application programming interface (API). This interface allows application functionality to be partitioned between mobile and stationary machines, increasing the autonomy of the mobile device through local operations. This in turn decreases user-perceived latency and wireless bandwidth requirements, while providing a framework to support disconnected operation. By exposing application-specific information to the system about data priority and access patterns the effectiveness of system-applied network optimizations is increased.

SWAN: an indoor wireless ATM network

Abstract: The SWAN (seamless wireless ATM network) project investigates architectural aspects of networks containing mobile hosts. The network model includes base stations connected via a wired, ATM infrastructure and a wireless, ATM last hop to a number of mobile hosts, ranging in computational and functional abilities from personal digital assistants to notebook computers. The FAWN (flexible adaptor for wireless networking) network interface card was developed as part of the implementation of a small SWAN network. It provides wireless, ATM channels using off-the-shelf FHSS modems which operate in the 2.4 GHz industrial, scientific and medical band, and use a sequence of radio channels of 1 MHz bandwidth to provide up to 625 kb/s raw bit rate. The first phase of the implementation has been completed and provides basic wireless ATM connectivity. This paper presents an overview of the SWAN network, followed by a description of the implementation which has been built to validate our initial architectural design.

Mobile Data Communications Systems

Abstract: From the Publisher: Brings you up to speed on mobile data system design, current and emerging wireless network and systems standards, and network architectures. Describes mobile data applications and wireless LANs, and analyzes and evaluates current technologies.

Arrangement for supplying local network emulation service over public connectionless atm-network

Abstract: The present invention relates to an arrangement for supplying local network emulation services over a public connectionless ATM-network. The ATM-network is in charge of connectionless data communication traffic by means of a broadband data service network (BDS). Private local networks (LAN) can be connected to the ATM-network to exchange traffic with other local networks. According to the invention the ATM-network emulates local networks so that the ATM-network can deal with the local network traffic, i.e. both public and private data communication services over ATM. According to the invention the BDS-network comprises servers which function as address resolvers for local network addresses and as local network relays for routing of the local network traffic via the ATM-network. The server uses preferably unit specific addresses (MAC) and local emulation groups (LEG) as address in the BDS-service.

Shared base stations for voice and data cellular telecommunications and method

Abstract: The present invention provides a system and method for using the brief time intervals between cellular telephone calls on a primary cellular network to transmit and receive data over a second data-only network. The invention uses the built-in capability of the primary network to monitor and track each call and to identify the relatively short-duration intervals between each call to pinpoint when a short burst of data from the second network can be transmitted without interfering with primary network calls. The data network includes a separate telephone exchange. Selected base stations of the primary cellular network are shared with the data-only network. Land lines or other connections link the data network exchange with the shared base stations. Preferably, the data network is accessible via a public packet data network. Data calls on the second network are directed to the shared base stations and inserted into the brief intervals between primary network calls. The data calls provide discontinuous, "virtual" connections between the users of the data network. A particular advantage of the invention is that it allows the cellular base stations, transceivers, and allocated frequencies to be shared between a primary and a secondary cellular telephone network, without interfering with or reducing the capacity of the primary network. The invention works with analog or digital primary cellular networks, including those using multiple access methods such as TDMA. A method of carrying out the invention is also disclosed.

Rednet: a wireless ATM local area network using infrared links

Abstract: Abstmct Rednet provides portable computers with an incxpensivc wireless network connection It is designed to support seamless end-to-end communication using the Asynchronous Transfer Mode (ATM) Rednet uses a Iowpower infrared transceiver operating at 2-5 Mbps over a distance of 4 meters The link layer protocol supports link sharing and transport of ATM cells over the link Ceiling mounted base stalions in each room act as gateways between the infrared link and rhe wired network Rednet is designed to support user mobility, so that users can roam from room to room and access network services in a location independent manner The paper describes our infrared physical layer and link layer protocols, presents an ovcrview of protocols for dynamic address assignment and conncction management, and summarizes the status of the work

Radio personal communications system and method for initiating communications between a base station and a cellular terminal

Abstract: Transceiver frequency and optionally power level are allocated to a radio personal communications system which includes a base station connected to a wire telephone network and a cellular terminal operating within a region of a wide area cellular network to minimize interference between communications over the wide area cellular network and communications between the base station and the cellular terminal. The same cellular terminal may thus be used to communicate over the lower cost wire network when within range of the base station and over the wide area cellular network otherwise. The frequency for communications between the cellular terminal and the base station are optionally assigned by the operator of the wide area cellular network so appropriate frequencies and power levels can be assigned for base stations, to minimize same channel interference with the wide area cellular network.

Radio personal communications system and method for selecting a frequency for use in communications between a base station and a cellular terminal

Abstract: Transceiver frequency and optionally power level are allocated to a radio personal communications system which includes a base station connected to a wire telephone network and a cellular terminal operating within a region of a wide area cellular network to minimize interference between communications over the wide area cellular network and communications between the base station and the cellular terminal. The same cellular terminal may thus be used to communicate over the lower cost wire network when within range of the base station and over the wide area cellular network otherwise. The frequency for communications between the cellular terminal and the base station are optionally assigned by the operator of the wide area cellular network so appropriate frequencies and power levels can be assigned for base stations, to minimize same channel interference with the wide area cellular network.

Architecture for wireless ATM networks

Abstract: This paper presents design considerations for future-generation personal communication networks (PCN) that integrate wireless access with the broadband wireline asynchronous transfer mode (ATM) network. Apart from the wireless ATM network architecture, some of the other issues that we report on include the design of the wireless-to-wireline network interfaces, and the specification of a wireless protocol reference model. Two examples are given of ways to accomplish diversity and related handoffs in the wireless ATM network.

A dynamic addressing scheme for wireless media access

Abstract: The key resource in a wireless LAN is the wireless medium itself. Since the bandwidth in wireless is typically much smaller than in wire, media access control in wireless is of critical importance in the operation of a wireless LAN. This paper proposes a protocol independent dynamic addressing scheme for wireless media access protocols, and discusses related systems and performance issues. Dynamic addressing allows spatial and temporal reuse of MAC addresses, thereby reducing the address size by a factor of 8. This reduces the control overhead in a MACAW style protocol by 30% to 70%, and produces an overall performance improvement of 5% to 33%. Dynamic addressing also serves as an enabling technology for two important features in wireless media access protocols, security and real-time support. We are implementing the dynamic addressing scheme as a part of the LCMACA wireless media access protocol.

Experiences with a Wireless Network in MosquitoNet

Abstract: As the trend towards smaller, lighter and more powerful computers continues, mobility and wireless connectivity become increasingly important. The MosquitoNet project is studying issues in wireless and mobile computing, and this paper presents our performance analysis and observations of one of the emerging wireless technologies: the Metricom Microcellular Digital Network (MCDN). Metricom provides one of the best combinations of bandwidth, coverage area and cost for a wireless data network. We find that the throughput of their radio devices is comparable to a modern modem, but the latency, or round-trip delay, is much higher. The maximum throughput we measured was 30-40 Kbits/second, but the minimum latency for even the smallest IP packet is at least 60ms. We have experimented with both the datagram and Hayes modem emulation modes of Metricom’s wireless radios. We are early users of the datagram mode, and our comparisons of these modes confirm two well-known but sometimes forgotten principles. First, packet switching allows more efficient sharing of resources than does circuit switching. Second, interfaces that are satisfactory for use by human beings often show their flaws, ambiguities and omissions when used as programming interfaces for software control of devices.

On the performance of packet-switched cellular networks for wireless data communications

Abstract: Cellular frequency reuse is known to be an efficient method to allow many wireless telephone subscribers to share the same frequency band. However, for wireless data and multi-media communications optimum cell layouts differ essentially from typical solutions for telephone systems. We argue that wireless radio systems for bursty message traffic preferably use the entire bandwidth in each cell. Packet queuing delays are derived for a network with multipath fading channels, shadowing, path loss and discontinuously transmitting base stations. Interference between cells can be reduced by appropriately scheduling transmissions or by `spatial collision resolution'.