Land Mobile Communication Systems Research Articles

Radio link design of cellular land mobile communication systems

A procedure for a radio link design of cellular land mobile radio systems is discussed. The relation between the prescribed total outage and the necessary margins for thermal noise and co-channel interference is first derived. It is then shown that the respective margins can be calculated separately. A simple and useful procedure for determining transmitter power and co-channel reuse distance is presented in concrete flowchart form. Based on this procedure, an example of a radio link design for a digital mobile telephone system is shown.

Burst error performance encountered in digital land mobile radio channel

Burst error characteristics are studied by using a Rayleigh and Nakagami-Rice fading simulator. Burst error length distribution estimated with fade duration is described. Thus burst length shortening by means of dual frequency diversity is a promising candidate in order to introduce safely forward error correction (FEC) coding into digital land mobile communication systems.

Statistical analysis of communications range and reliability in the presence of interference

A statistical method is developed for analysis of interference in land mobile communications systems. Reduction of communication range and degradation of system reliability are calculated. This method can be used for cases in which a desired signal is transmitted by a base station (or mobile unit) and received by a mobile unit (or base station) and is interfered with by a signal transmitted either by a fixed station or a mobile unit. The spatial probability distribution of mobile units is considered. The method is applicable to any frequency band for which path loss statistics are known, and an example of this method is given which calculates reduction in communication range, area, and degradation of communication reliability for different values of splatter protection, and distributions of mobile units.

A Model for Assessing the Impact of an Impulsive Noise Process on Land-Mobile Communication

This paper develops a statistical model with which the impact of a given noise random process upon a land-mobile communication system (LMCS) can be assessed. This model is useful for computing an upper bound for the fraction of communication-system messages which are affected by any given EMI at any given interference level. Applications of the model include, for example, bounding the interference effects on land-mobile communication of the EMI produced by arbitrary electrical apparatus.

The Bonneville power administration land-mobile communications system

Radio coordinated traffic light control permits the elimination of the conventional multiconductor cable which must tie together all traffic lights in a system. A VHF carrier modulated with audio-frequency control tones permits the radio coordinated system to perform the same as with the use of a cable plus the possibility of gaining additional benefits. All conventional traffic light control equipment may be used without modification. Several systems have been installed with complete success, gaining advantages in cost and flexibility. It may be expected that this form of control will grow rapidly within the next few years.