A quantification of link budget differences between the cellular and PCS bands

The median propagation loss in the personal communication services (PCSs) band (near 1.9 GHz) is generally recognized to be 9-10 dB greater than that in the cellular band (near 850 MHz). It would be highly desirable to make up this deficit in order to minimize the infrastructure cost of PCS service startup. This goal is aided by three factors favorable to operation at PCS frequencies. First, the vertical pattern gain of the base-station antenna, for the same size, will be more than 3 dB higher at 1.9 GHz. Second, the gain derived from using base-station antenna diversity on the uplink will be greater at 1.9 GHz. The third factor is lower man-made noise at 1.9 GHz, especially in urban areas. We have carefully examined all these factors in order to quantify the link budget differences between the two bands for three types of environment, namely, urban, suburban, and rural. We find that link budget parity (meaning the same allowable cell sizes) can be achieved in all three environments with fairly modest remedies. These include the use of tower-top electronics and minor increases in downlink power. An alternative remedy is to use four-branch maximal ratio combining (MRC) at the base station, which would provide a natural transition toward the deployment of adaptive arrays.