Influence of Different Factors on X-Map Estimation in LTE

Information about the radio coverage is essential for network planning and network optimization. In order to obtain the necessary information, planning tools are used which are in some aspects inaccurate due to, e.g., inaccurate input data, simplifications in the applied propagation models, and changes in the environment or traffic distribution. Thus, the planning tools have to be optimized using measurement campaigns. For this, drive/walk tests have to be performed which are not ideal since only a limited part of the network can be covered due to the costs and access restrictions, and only a snapshot of the conditions in the field is captured. Therefore, we introduce the concept of the X-map estimation function which continuously monitors the network and estimates the spatial network performance by processing the UE reports in a geographic map with overlay performance information, referred to as an X-map. Two different approaches for creating X-maps are evaluated in this paper. We analyze the influence of the positioning accuracy, the UE measurement accuracy, and the number of measurements taken on the accuracy of the resulting X-maps. We show that the influence of the different factors on the accuracy of the X-maps depends on the used approach and that the positioning accuracy and the number of measurements taken have the largest impact.