Radio Port Spacing in Low Tier Wireless Systems

Abstract

The capacity of a low tier wireless system is dependent on the distance between adjacent radio ports (RPs). Maximum port spacing, determined by a RP’s maximum coverage area, is important where population density is low. Minimum port spacing is important where population density is high, as is the case in congested urban areas. Minimum port spacing imposes a significant capacity constraint and has a direct impact on the amount of spectrum needed in a low tier wireless system.

This paper develops estimates for maximum and minimum port spacing. These estimates can be used to lay out such systems and to estimate the amount of spectrum that will be required to serve a given population density. We consider both high rise and low rise environments and the use of both directional and omnidirectional antennas.

We assume that the carrier to interference ratio (C/I) must be held above certain levels in fixed and mobile service. A propagation model is used to estimate the C/I ratio as a function of RP spacing and other variables. This allows us to estimate which RP spacings will provide acceptable performance and which will not. The results of this approach are estimates of maximum and minimum RP spacing in a variety of environments.