Influence of Positioning Error on X-Map Estimation in LTE

Today, the network operators have to perform drive/walk tests when planning and optimizing their networks. These drive/walk tests are costly and time-consuming, cover only a limited part of the network, and capture only a snapshot in time. To overcome these difficulties, the mobile devices in the network can be used as probes by continuously reporting the observed service quality together with their positions. In this paper, we introduce the concept of X-map estimation, which is a function that processes the measurement data into a geographic map with overlay performance information, referred to as an X-map. By continuously processing measurements, the X-map estimation function approximates the spatial characteristics of the network performance and therefore reduces the costs of drive/walk tests. Additionally, X-maps can be used by Self-Organizing Networks (SON), especially in functionalities that address optimization of coverage, capacity, and quality. In this paper, we introduce two approaches for determining X-maps and we analyze the influence of the applied positioning method on the accuracy of the X-maps. We show that the accuracy of the positioning technique can have a significant impact on the accuracy of the X-map.