Showing papers on "Cellular network published in 1987"

A design concept for reliable mobile radio networks with frequency hopping signaling

Abstract: The design of a packet radio network must reflect the operational requirements and environmental constraints to which it is subject. In this paper, we outline those features that distinguish the High Frequency (HF) Intra Task Force (ITF) Network from other packet radio networks, and we present a design concept for this network that encompasses organizational structure, waveform design, and channel access. Network survivability is achieved through the use of distributed network control and frequency hopping spread-spectrum signaling. We demonstrate how the execution of the fully distributed Linked Cluster Algorithm can enable a network to reconfigure itself when it is affected by connectivity changes such as those resulting from jamming. Additional resistance against jamming is provided by frequency hopping, which leads naturally to the use of code division mutiple access (CDMA) techniques that permit the simultaneous successful transmission by several users. Distributed algorithms that exploit CDMA properties have been developed to schedule contention-free transmissions for much of the channel access in this network. Contention-based channel access protocols can also be implemented in conjunction with the Linked Cluster network structure. The design concept presented in this paper provides a high degree of survivability and flexibility, to accommodate changing environmental conditions and user demands.

A simulator study of the safety implications of cellular mobile phone use

Abstract: The mobile telephone industry is growing rapidly as user costs decline and cellular networks are introduced in urban areas throughout the U.S. Well over 80,000 mobile phone units are in use in California alone. Industry representatives cite numerous safety benefits associated with mobile phone use and contend that the phones contribute no more of a distraction to drivers than car radios. Mobile phones can lead to more timely reporting of accidents, stalled vehicles, drinking drivers, and other emergency situations. Just as clearly, mobile phones could conceivably create a safety hazard by distracting drivers from the control of their vehicles. An interactive driving simulator developed by STI was used to investigate the impacts of different types of mobile phone design, use, and mounting locations on driver performance in negotiating a simulated route. Along the route drivers were required to negotiate curves, avoid obstacles, and respond to various road signs. Data on lane position and speed were collected along the routes, making it possible to compare driver performance when no task was required (the baseline case) with performance over similar segments while dialing a phone, receiving a call, or tuning a radio. Seventy-two subjects were segregated by sex, age, and past experience with mobile phone use in analyzing driver performance. This paper discusses the experimental approach, methods, and conclusions; and, with one major exception, supports the industry contentions. Keywords: Driver distraction;

Idle-signal casting multiple access with collision detection (ICMA-CD) for land mobile radio

Abstract: A population of mobile terminals communicating with a central station over a packet-switched multiple-access radio channel is investigated. In land mobile radio communication, in which terminals cannot sense the carrier transmitted from other terminals (either because they are out-of-range or obstructed), a central controlled multiple access system in which a central station broadcasts idle/busy information of the access channel is used for multiplexing the packets from the terminals. Idle-signal casting multiple access (ICMA), which is a practical application of this central controlled system, has been used in the Nippon Telegraph and Telephone Public Corp. (NTT) mobile phone system for some years. ICMA-CD, which is an advanced ICMA scheme characterized by collision detection and evaluates its improved throughput, channel capacity and loss probability in a mobile radio fading environment with restrictions on retransmission, is proposed. It is clarified that ICMA-CD is suitable for the mobile multiple access scheme, especially in the case where packet detection delay and collision recovery time are short and offered traffic is heavy.

Conception and performance of the cellular digital mobile radio communication system CD 900

Abstract: The cellular digital radio communication system CD 900 supplies millions of mobile subscribers per network with voice and data service. It applies a digital wideband TDMA-process allowing up to 330 traffic channels within 24 MHz to be allocated to one base station. A cluster of three becomes possible by its excellent interference suppression features resulting from the utilization of multipath signals by an adaptive matched filtering process realized with a digital signal processor. CD 900 is designed as to satisfy the demand for a mobile communication mass market as well as for its adaption to modern digital transmission networks including ISDN.

A digital narrow-band cellular system

Abstract: In many areas of the United States, cellular systems are nearing full capacity. To alleviate this problem and allow for further growth, a compatible, more spectrally efficient system is needed. In addition, as the telecommunications network becomes fully digital, it will be desirable to provide digital services in cellular systems. In this paper a narrow-band digital FDMA cellular telecommunications system is proposed. The system uses low bit rate speech coding in conjunction with a linear modulation system to provide a spectrally efficient cellular service. The channel modem uses digital signal processing techniques. Because the system is digital, security and encryption, as well as data services, can be readily implemented. A cellular ISDN signaling channel will be incorporated as an integral part of the system. The system has been designed to provide immunity over a large range of delay spread conditions.

Mobile telephony in the next decade

Abstract: The main purpose of this paper is to analyse the technical future of cellular radio. It is shown that the best technical solution for the end of the century is a new concept based on digital TDMA technology. It is also concluded that the growth potential for current analog systems is enough to take care of the demand up to a time when the new technology is available.

Transmission of data over the cellular telephone network

Abstract: Ameritech Mobile Communications, Inc. introduced Cellular Data to it's five state region in September of 1985. The past year and a half has brought to light some of the pitfalls associated with this service as well as some new and exciting uses. It has been a time of learning, of educating and trialing for customers of Ameritech Mobile and employees. It is the purpose of this paper to relate the problems encountered, the solutions presently available and their viability. Marketing considerations will be touched upon as well as what technologies yet need to be developed.

Cellular networking functionality a application

Abstract: This paper describes the implementation, the thorough level of testing performed, the framework for billing, and the high level performance metrics of cellular networking as developed by AT&T for its AUTOPLEX family of cellular telecommunications systems.

Analysis of a multi-hop CDMA packet radio network

Abstract: A multi-hop packet radio network employing Code Division Multiple Access (CDMA) is considered. The network is modeled as a system of interacting queues, and sufficient conditions for the stability of the queueing system model are obtained. Also, an upper bound on the network mean packet delay is found. The obtained results are used to characterize the throughput performance of a radio network employing frequency-hop spread-spectrum signaling.