Time Dispersion Estimation for Mobile Radio Network Planning

In radio network planning, the goal is to specify optimalbase station locations, service areas, antenna patterns and handoverstrategies for a given mobile radio system. The system performanceis fixed and the radio channel is subject to optimisation.Network planning requires channel characteristics thatprovide information about the expected sendee quality, especiallythe outage probability. The channel description must onlyperform as a qualitative measure of an actual receiving area.Power delay profiles are a convenient and very common descriptionof channel time dispersion, which can be easily physicallyunderstood as footprints of individual reflected or scatteredpaths, and provide a capability to a network planning engineerto discover areas of heavy time dispersion and importantscattering regions on the terrain. This in turn enables better assessmentof base station sites, antenna pattern selection, sen,iceregion (cell) shaping (handover criteria) and solving networkproblems.Time dispersion is mostly found to be the cause of poor coverageby excluding other possible causes. In cases where fieldstrength coverage does not overlap and base station sites cannotbe moved, shaping antenna directivity will be the only way toeliminate excessive time dispersion.