Frequency assignment for land mobiles in large urban areas

Using the frequency assignment model of M.C. Delfour and G.A. DeCouvreur (see IEEE Trans. on Electromagn. Compatibility 1987), recent developments which further increases the capacity of the underlying assignment grid, incorporate a predetermined distribution of single-user and multiuser frequencies, and handle gaps in the band are presented. The method is applied to the present user distribution for the VHF land mobile from 138 to 174 MHz band in Montreal. The capacity increased from 25 channels/km/sup 2/ to 30 channels/km/sup 2/, i.e. an increase of about 58%. It is conjectured that a larger spectrum would yield even higher density. It is now possible to take into account gaps in a given frequency band. The analysis shows that they do not significantly affect the spectrum assignment process. Careful design also provides some control of the effect of gaps. Special techniques have been developed to produce a model that provides 50% of the spectrum for single-user and 50% for multiusers channels.<>