Showing papers on "Mobile telephony published in 1972"
TL;DR: It was found that the strategy that chooses a channel to be assigned at a base station so that the distance to the next base station using the same channel is a minimum, performs better than a strategy that minimizes the mean square distance toThe next "in use" base stations on both sides.
Abstract: When more than one radio channel is available to serve a mobile customer in a large-scale mobile communications system the strategy used to make the assignment has an effect on system performance. Performance characteristics for five different assignment strategies obtained from a computer simulation are compared in this paper. It was found that the strategy that chooses a channel to be assigned at a base station so that the distance to the next base station using the same channel is a minimum, performs better than a strategy that minimizes the mean square distance to the next "in use" base stations on both sides. Also, it was found that choosing the first available channel encountered in a channel search is a strategy that produces reasonably good system performance.
114 citations
TL;DR: As the number of radio channels available to a communication system increases, the system becomes more efficient in handling the fluctuations in offered traffic and changing the radio-channel reuse interval also affects the per-channel traffic carried by a dynamic-channel-assignment system.
Abstract: Dynamic channel assignment in mobile communications systems is able to cope with varying nonuniform spatial user demand. It also readily handles the normal randomness in offered traffic. This study presents system performance data for radio systems having 8, 20, 40, 80, and 120 radio channels available and a radio-channel reuse interval of 4 base-station coverage areas. Data are also presented that compare performance of a 30 radiochannel system with a reuse interval of 3 base stations, a 40 radiochannel system with a reuse interval of 4 base stations, and a 50 radio-channel system with a reuse interval of 5 base stations. The results are obtained from a computer simulation of a onedimensional network laid out along a line. As the number of radio channels available to a communication system increases, the system becomes more efficient in handling the fluctuations in offered traffic. Changing the radio-channel reuse interval also affects the per-channel traffic carried by a dynamic-channel-assignment system.
23 citations
01 Jan 1972
TL;DR: The effects which multipath propagation, Gaussian noise, and implusive noise have on digital errors are analyzed and recommendations for improving the noisy, fading digital channel are made.
Abstract: This thesis is aimed at the problem of quickly and accurately communicating digital data between fixed and mobile (either vehicle-mounted or hand-held) radio stations. Digital error is of prime concern and the effects which multipath propagation, Gaussian noise, and implusive noise have on digital errors are analyzed. The importance of other analyses such as economic factors, interrogation procedures, or analog transmission might be peculiar to land mobile communication, but the recommendations for improving the noisy, fading digital channel should have broader application and a more general appeal.
6 citations
01 Jan 1972
TL;DR: In this paper, a short historical sketch of mobile communications in Japan, technical problems and future prospects are described, and major problems of future mobile communica- tion, for example, radio propagation, controlling, and switching and radio equipment involved in meeting the future demands of a large number of subscribers over widespread service areas.
Abstract: After a short historical sketch of mobile communications in Japan, technical problems and future prospects are described. The peculiarities characteristic of mobile communication include complicated radio propagation and requirements for continuous communication and determination of mobile subscribers' location. This paper discusses major problems of future mobile communica- tion, for example, radio propagation, controlling, and switching and radio equipment involved in meeting the future demands of a large number of subscribers over widespread service areas. Effective use of an electronic switching system will enable the mobile com- munication network to be integrated with existing fixed communica- tion networks.