Cell radius inaccuracy: a new measure of coverage reliability

A robust method for determining the boundaries of cells and the associated reliability of the radio frequency (RF) coverage within these boundaries is presented. The procedure accurately determines the effective cell radius using a linear regression of the RF signal strength samples. The accuracy of this estimate is quantified both as a radius uncertainty (e.g., ±100 m) and as a coverage (i.e., area/edge) reliability error through: (1) simulation; (2) analysis of real data; and (3) theoretical analysis. It is shown that if the estimate of the cell radius meets the desired accuracy, then the corresponding estimates of coverage reliability (both area and edge) are more than sufficiently accurate. Through a sensitivity analysis, it is discovered that estimating the cell radius is a much more critical step in determining the quality of RF coverage than the more common practice of simply estimating the area reliability. In addition, a formula for estimating area reliability is given and shown to be more accurate than can be obtained by current approaches. The verification method presented is particularly useful in wireless planning since it effectively determines the geographic extent of reliable RF coverage. It is recommended that radio survey analyses select cell radius estimation as the preferred method of coverage verification