Adjacent channel selectivity for land mobile radio systems

A variety of analogue and digital radio systems with different channel bandwidths operate in the land mobile frequency bands. Spectrum congestion in some of these bands, coupled with advances in DSP technology, vocoding technology as well as modulation and coding techniques are driving the move towards narrow-band channels. It therefore became essential to have an algorithm to carry out interference analysis between transmitters and receivers that may be utilizing different channel bandwidths or even different transmission technologies. To complicate this issue further, standards for radio receivers are no longer mandatory in Canada and the United States. At the same time, many of the radio receivers in use are proprietary. As a result, a need arose for the development of models for the adjacent channel frequency selectivity of the receiver. In this paper, models are developed for the interfering signal power spectral density and for the frequency selectivity of radio receivers. These models are intended for interference prediction among land mobile radio systems